%%
@article{Everitt:1986p1558,
Author = {Everitt, HO and Skatrud, DD and DeLucia, FC},
Title = {Dynamics and tunability of a small optically pumped cw
far-infrared laser},
Journal = {Applied Physics Letters},
Volume = {49},
Number = {16},
Pages = {995-997},
Publisher = {AIP Publishing},
Year = {1986},
Month = {December},
ISSN = {0003-6951},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=A1986E435400003&SID=2Dfb9AFL3jni2%40d8oGp&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {We report the development of an ultrasmall, optically pumped
cw far-infrared (FIR) laser that provides substantial
tunability. This laser operates at pressures significantly
higher than the maximum allowed by currently accepted
theory. We also report the development of a new theoretical
model for diffusion limited optically pumped FIR lasers
which accounts for this behavior. It is shown that the
consideration of additional higher energy vibrational
states, along with appropriate energy transfer mechanisms,
fundamentally alters the behavior of the system in the high
pressure, high pump intensity regime. Although 13CH3F is
used for both the experimental demonstration and the
theoretical model, the concept is general and should apply
to all diffusion relaxed FIR lasers.},
Language = {English},
Doi = {10.1063/1.97469},
Key = {Everitt:1986p1558}
}
@article{MCCORMICK:1987p1559,
Author = {Mccormick, RI and Everitt, HO and De Lucia and FC and Skatrud,
DD},
Title = {Collisional energy transfer in optically pumped far-infrared
lasers},
Journal = {Ieee Journal of Quantum Electronics},
Volume = {23},
Number = {12},
Pages = {2069-2077},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {Duke Univ,Dept Phys,Durham,Nc 27706},
Institution = {Duke Univ,Dept Phys,Durham,Nc 27706},
Year = {1987},
Month = {January},
ISSN = {0018-9197},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=A1987L219400005&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {A numerical simulation of collisional energy transfer in
optically pumped far-infrared (OPFIR) lasers is presented
along with a discussion of each collisional process and how
it affects laser operation. A simulation is required to
adequately describe these lasers because of the relatively
large number of nonequilibrium states and thermal pools that
are significant in the dynamics of their excitation and
relaxation. The results of diagnostic studies and
theoretical considerations are used to restrict the numbers
of degrees of freedom so that a numerically tractable and
physically satisfying model results. The resulting
simulation accurately characterizes collisional energy
transfer in these lasers over a much wider range of physical
conditions than is possible with analytic models. These
conditions include the very low pressure regimes most suited
to the recovery of fundamental molecular collisional energy
transfer parameters. Significantly for OPFIR laers, it
predicts a new operating regime, which has been
experimentally verified, that leads to small, tunable CW
laser systems. Copyright © 1987 by The Institute of
Electrical and Electronics Engineers, Inc.},
Language = {English},
Doi = {10.1109/JQE.1987.1073302},
Key = {MCCORMICK:1987p1559}
}
@article{fds325480,
Author = {Everitt, HO and McCormick, RI and DeLucia, FC and Skatrud,
DD},
Title = {DIAGNOSTICS, MODELING, AND DEMONSTRATION OF A COMPACT,
TUNABLE FAR-INFRARED LASER.},
Pages = {160},
Year = {1987},
Month = {January},
ISBN = {0936659513},
Abstract = {A program of diagnostic studies and theoretical modeling has
resulted in development of a tunable optically pumped
far-infrared (FIR) laser that is very compact. The
tunability of this laser comes about because it operates at
pressures significantly higher than the maximum allowed by
previously accepted theory. Typical dimensions for the
compact FIR laser are a radius of 3 mm and a length of 150
mm. Because of the small diameter, the pump intensity is
high even with modest pumping powers. At high pressures, the
additional highly excited vibrational states become very
important, and operation much above the cutoff pressure
predicted by conventional theory becomes possible. The key
element of the model, which explains the high-pressure
operation of the laser is the inclusion of the additional
highly excited vibrational states and the associated energy
transfer processes. A very simple nonoptimized version of
this laser has provided a tunability of 100 MHz. The model
predicts that optimization of the device will produce 1000
MHz of tunability. Although **1**3CH//3F was used for all
this work, the concept is general and would appear to apply
to all diffusion-relaxed FIR lasers.},
Key = {fds325480}
}
@article{1987JOSAB...4..182E,
Author = {Everitt, Henry O and McCormick, Rodney I. and Delucia, Frank
C. and Skatrud, David D.},
Title = {Diagnostics, modeling, and demonstration of a compact,
tunable far-infrared laser (A)},
Journal = {Journal Of The Optical Society Of America B-Optical
Physics},
Volume = {4},
Pages = {182},
Year = {1987},
Month = {February},
url = {http://adsabs.harvard.edu/abs/1987JOSAB...4..182E},
Abstract = {Not Available},
Key = {1987JOSAB...4..182E}
}
@article{fds332005,
Author = {McCormick, RI and Skatrud, DD and Everitt, HO and De Lucia,
FC},
Title = {MODELING OF COLLISIONAL ENERGY TRANSFER IN OPTICALLY PUMPED
FAR INFRARED LASERS.},
Journal = {Conference Digest International Conference on Infrared and
Millimeter Waves},
Pages = {372-373},
Year = {1987},
Month = {December},
Abstract = {Optically pumped far-infrared (OPFIR) lasers have been the
subject of extensive theoretical and experimental
investigations. The authors have used the results of a large
experimental data set to appropriately select the degrees of
freedom for a numerical simulation of OPFIR lasers. The
tunability and sensitivity of this technique has allowed the
probing of all states that participate in the lasing and
insured that no important states were neglected.},
Key = {fds332005}
}
@article{fds332006,
Author = {McCormick, RI and Skatrud, DD and Everitt, HO and De Lucia,
FC},
Title = {EXPERIMENTAL INVESTIGATION OF ENERGY TRANSFER IN OPTICALLY
PUMPED FIR LASERS.},
Journal = {Conference Digest International Conference on Infrared and
Millimeter Waves},
Pages = {374-375},
Year = {1987},
Month = {December},
Abstract = {The authors conducted a time-resolved double-resonance study
of **1**3CH//3F to explore the rotational and vibrational
energy-transfer processes in this optically pumped
far-infrared (OPFIR) laser. The use of a Q-switched CO//2
laser and sensitive, tunable millimeter and submillimeter
techniques allowed the probing of not only the gain profile
of the laser transition, but also many other states that are
collisionally coupled and play important roles in the
energy-transfer process.},
Key = {fds332006}
}
@article{fds325479,
Author = {Everitt, HO and De Lucia and FC and Skatrud, DD},
Title = {SMALL TUNABLE OPTICALLY PUMPED FAR INFRARED
LASER.},
Journal = {Conference Digest International Conference on Infrared and
Millimeter Waves},
Pages = {306-307},
Year = {1987},
Month = {December},
Abstract = {A small-diameter continuous-wave far-infrared (FIR) laser
that can provide approximately 100-MHz spectrally pure
tunability has been developed and studied both
experimentally and theoretically. Operation of this laser at
pressures significantly greater than the maximum allowed by
previously accepted theory yields the larger tunability. The
model includes additional high-energy vibrational states and
appropriate energy transfer mechanisms that fundamentally
alter the behavior in the high-pressure, high-pump-intensity
regime. Although **1**3CH//3F is used for both the
experimental demonstration and the theoretical model, the
concept is general and should apply to all
diffusion-deactivated FIR lasers.},
Key = {fds325479}
}
@article{fds342769,
Author = {CORNEY, R and EVERITT, H and HOWELLS, A and CROWTHER,
M},
Title = {PSYCHOSEXUAL MORBIDITY FOLLOWING GYNECOLOGICAL
OPERATIONS},
Journal = {Free Woman},
Pages = {771-777},
Publisher = {PARTHENON PUBLISHING GROUP LTD},
Editor = {VANHALL, EV and EVERAERD, W},
Year = {1989},
Month = {January},
ISBN = {1-85070-264-0},
Key = {fds342769}
}
@article{1989JChPh..90.3520E,
Author = {Everitt, HO and De Lucia and FC},
Title = {A time-resolved study of rotational energy transfer into A
and E symmetry species of 13CH3F},
Journal = {The Journal of Chemical Physics},
Volume = {90},
Number = {7},
Pages = {3520-3527},
Publisher = {AIP Publishing},
Year = {1989},
Month = {January},
ISSN = {0021-9606},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1989JChPh..90.3520E&link_type=EJOURNAL},
Abstract = {Rotational energy transfer processes into the A and E
symmetry species of the symmetric top molecule 13CH3F have
been studied. In this time-resolved double resonance
experiment a tunable millimeter/ submillimeter wave
spectrometer was used to monitor the change in strength of
rotational transitions in the v3 vibrational state after a
Q-switched CO2 laser pumped the K = 3, J = 5 level in v3. A
simple numerical simulation of rotational energy transfer
allowed the 13CH3F system to be modeled and collisional
energy transfer rates to be obtained from the data. Two
important processes were studied. The first, a process that
obeys the spin statistic selection rule ΔK = 3n has a rate
of 29 ±6 ms-1 mTorr-1. The second, a vibrational quantum
number swapping collision that effectively transfers
population between the A and E symmetry species and thereby
transcends the spin statistic selection rule, has a rate of
6.6 ±0.7 ms -1 mTorr-1, about 1.4 gas kinetic collisions.
The numerical simulations and these rates, along with
previous measurements of the ΔJ= ±1 rate and vibrational
decay rates, provide an accurate characterization for a
large body of varied experimental data. © 1989 American
Institute of Physics.},
Doi = {10.1063/1.456665},
Key = {1989JChPh..90.3520E}
}
@article{Everitt:1990p1555,
Author = {Everitt, Henry O and DeLucia, FC},
Title = {ROTATIONAL ENERGY-TRANSFER IN CH3F - THE DELTA-J=N,
DELTA-K=0 PROCESSES},
Journal = {Journal Of Chemical Physics},
Volume = {92},
Number = {11},
Pages = {6480--6491},
Year = {1990},
Month = {January},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=A1990DE14600016&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Language = {English},
Doi = {10.1063/1.458283},
Key = {Everitt:1990p1555}
}
@article{1990JChPh..92.6480E,
Author = {Everitt, HO and DeLucia, FC},
Title = {Rotational energy transfer in CH3F: The ΔJ=n,
ΔK=0 processes},
Journal = {The Journal of Chemical Physics},
Volume = {92},
Number = {11},
Pages = {6480-6491},
Publisher = {AIP Publishing},
Year = {1990},
Month = {January},
ISSN = {0021-9606},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990JChPh..92.6480E&link_type=EJOURNAL},
Abstract = {We report the measurement of the rates of ΔJ=n, ΔK=0(|n|
≤ 10) processes for CH3F-CH3F collisions at 300 K. The
data are derived from a time-resolved millimeter/
submillimeter-infrared double resonance investigation of
both the 12CH3F and the 13CH3F isotopic species. The rates
were obtained via a nonlinear least-squares analysis of the
data using a numerical simulation of rotational energy
transfer in methyl fluoride. These rates are shown to be
quantifiable in terms of the scaling law of infinite order
sudden collision theory and the statistical power gap law.
As a result, the numerous ΔJ=n, ΔK=0(|n| > 1) rates can be
understood in terms of only two parameters, independent of
isotopic species. Using these results and the results of our
earlier studies of K-changing processes, we discuss how
rotational energy transfer in the CH3F system in general can
be described in terms of a small number of collisional
processes and parameters. © 1990 American Institute of
Physics.},
Doi = {10.1063/1.458283},
Key = {1990JChPh..92.6480E}
}
@phdthesis{Everitt:1990p846,
Author = {Everitt, Henry O},
Title = {Collisional Energy Transfer in Methyl Halides},
Publisher = {Duke University},
Organization = {Department of Physics},
Institution = {Department of Physics},
Year = {1990},
Month = {August},
Key = {Everitt:1990p846}
}
@article{CROWNOVER:1990p1550,
Author = {Crownover, RL and Everitt, HO and De Lucia and FC and Skatrud,
DD},
Title = {Frequency stability and reproducibility of optically pumped
far-infrared lasers},
Journal = {Applied Physics Letters},
Volume = {57},
Number = {27},
Pages = {2882-2884},
Publisher = {AIP Publishing},
Organization = {USA,RES OFF,RES TRIANGLE PK,NC 27709},
Institution = {USA,RES OFF,RES TRIANGLE PK,NC 27709},
Year = {1990},
Month = {December},
ISSN = {0003-6951},
url = {http://access.isiproducts.com/custom_images/wok_failed_auth.html},
Abstract = {Direct measurements of the gain profile of optically pumped
far-infrared lasers show that large shifts in the laser
frequency can be caused by the absorption from thermal
molecules on the laser transition. The absorption shifting
greatly exacerbates pump frequency deviations, resulting in
an extreme sensitivity to pump offsets and drifts. This
pressure-dependent shifting mechanism is not present in
transversely pumped lasers, which explains their superior
frequency reproducibility compared to longitudinally pumped
lasers, and reconciles two apparently conflicting results
regarding laser stability.},
Language = {English},
Doi = {10.1063/1.103765},
Key = {CROWNOVER:1990p1550}
}
@article{Goyette:1992p1553,
Author = {Goyette, TM and MCCORMICK, RI and DeLucia, FC and Everitt,
Henry O},
Title = {COLLISIONS AND ROTATIONAL SPECTROSCOPY},
Journal = {Journal Of Molecular Spectroscopy},
Volume = {153},
Number = {1-2},
Pages = {324--339},
Organization = {USA,RES OFF,RES TRIANGLE PK,NC 27709},
Institution = {USA,RES OFF,RES TRIANGLE PK,NC 27709},
Year = {1992},
Month = {January},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=A1992HT47800030&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Language = {English},
Key = {Goyette:1992p1553}
}
@article{fds314086,
Author = {Goyette, TM and McCormick, RI and De Lucia and FC and Everitt,
HO},
Title = {Collisions and rotational spectroscopy},
Journal = {Journal of Molecular Spectroscopy},
Volume = {153},
Number = {1-2},
Pages = {324-339},
Publisher = {Elsevier BV},
Year = {1992},
Month = {January},
ISSN = {0022-2852},
url = {http://dx.doi.org/10.1016/0022-2852(92)90481-3},
Abstract = {Motivated by Oka's early work on molecular collisions and
especially collision-induced rotational transitions, this
paper addresses progress in these areas. Particular
attention is paid to recent extensions to lower energy
collisions of astrophysical significance and to questions
about the relation between experimental observables and the
more fundamental molecular interactions. ©
1992.},
Doi = {10.1016/0022-2852(92)90481-3},
Key = {fds314086}
}
@article{BOWDEN:1993p1556,
Author = {BOWDEN, CM and DOWLING, JP and Everitt, Henry
O},
Title = {DEVELOPMENT AND APPLICATIONS OF MATERIALS EXHIBITING
PHOTONIC BAND-GAPS - INTRODUCTION},
Journal = {Journal Of The Optical Society Of America B-Optical
Physics},
Volume = {10},
Number = {2},
Pages = {280--280},
Organization = {USA,RES OFF,RES TRIANGLE PK,NC 27709},
Institution = {USA,RES OFF,RES TRIANGLE PK,NC 27709},
Year = {1993},
Month = {January},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=A1993KK74500013&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Language = {English},
Key = {BOWDEN:1993p1556}
}
@article{fds318442,
Author = {Bowden, CM and Dowling, JP and Everitt, HO},
Title = {Development and applications of materials exhibiting
photonic band gaps},
Journal = {Journal of the Optical Society of America
B},
Volume = {10},
Number = {2},
Pages = {280-282},
Publisher = {The Optical Society},
Year = {1993},
Month = {January},
url = {http://dx.doi.org/10.1364/JOSAB.10.000280},
Doi = {10.1364/JOSAB.10.000280},
Key = {fds318442}
}
@article{Everitt:1993p1548,
Author = {Everitt, HO and de Lucia, FC},
Title = {The temperature dependence of fast vibrational energy
transfer processes in methyl fluoride},
Journal = {Molecular Physics},
Volume = {79},
Number = {5},
Pages = {1087-1101},
Publisher = {Informa UK Limited},
Organization = {OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210},
Institution = {OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210},
Year = {1993},
Month = {August},
url = {http://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=Papers&UT=A1993LR63800013&SID=4FnIC7F76BnjjOEmGgG&Init=Yes&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {The temperature dependencies of two fast vibrational energy
transfer processes in methyl fluoride (CH3F) have been
measured between 120K and 400 K by means of time-resolved
millimetre/submillimetre-infrared double resonance
spectroscopy. The first of these processes, a resonant
vibrational swapping process between the ground vibrational
state and the v3 = 1 (V3) vibrational state, effectively
transfers population between states of A and E symmetry. A
rapid increase in cross section with decreasing temperature
was observed for this process, a result in excellent
quantitative agreement with semi- classical theory of near
resonant vibrational collisions. The second process, which
transfers population between the v3 and v6 = 1 (v6)
vibrational states, was found experimentally to have a much
weaker temperature dependence. From this result and from
additional experimental observations of symmetry
type-sensitive energy transfer into v6, the energy transfer
between v3and v6 was demonstrated to result from a
‘direct’ vibrational energy transfer rather than from an
‘indirect’ vibrational swap process. © 1993 Taylor and
Francis Ltd.},
Language = {English},
Doi = {10.1080/00268979300101851},
Key = {Everitt:1993p1548}
}
@article{Goyette:1995p1551,
Author = {Goyette, TM and Guo, W and De Lucia and FC and Swartz, JC and Everitt, HO and Guenther, BD and Brown, ER},
Title = {Femtosecond demodulation source for high-resolution
submillimeter spectroscopy},
Journal = {Applied Physics Letters},
Volume = {67},
Number = {25},
Pages = {3810},
Publisher = {AIP Publishing},
Organization = {DUKE UNIV,DEPT PHYS,DURHAM,NC 27708},
Institution = {DUKE UNIV,DEPT PHYS,DURHAM,NC 27708},
Year = {1995},
url = {http://dx.doi.org/10.1063/1.115391},
Abstract = {A new continuously tunable submillimeter source for
spectroscopy and other high-resolution applications has been
developed. In this source the optical spectrum of a
mode-locked femtosecond laser is downconverted into the
submillimeter region by the demodulation process of a
photoconductive switch. The power generated is subsequently
radiated into free space by an antenna which is integrated
along with the switch on low-temperature grown GaAs. The
very high resolution is ultimately traceable to the cavity
length of the laser and the stable mode-lock frequency which
results. Among the most important attributes of the sources
are straightforward absolute frequency calibration, very
high spectral purity, and the potential for spectral
multiplexing. © 1995 American Institute of
Physics.},
Language = {English},
Doi = {10.1063/1.115391},
Key = {Goyette:1995p1551}
}
@incollection{Everitt:1995p6501,
Author = {Everitt, HO and de Lucia, FC},
Title = {Rotational Energy Transfer in Small Polyatomic
Molecules},
Journal = {Advances in Atomic, Molecular and Optical
Physics},
Volume = {35},
Number = {C},
Pages = {331-400},
Booktitle = {Advances in Atomic, Molecular, and Optical
Physics},
Publisher = {Elsevier},
Organization = {USA, Res Off, Res Triangle Pk, NC 27708 USA},
Institution = {USA, Res Off, Res Triangle Pk, NC 27708 USA},
Year = {1995},
Month = {January},
url = {http://dx.doi.org/10.1016/S1049-250X(08)60166-4},
Abstract = {This chapter discusses rotational energy transfer (RET) in
small polyatomic molecules. It focuses on incoherent
state-to-state rates that result from collisions between
like molecules and on the relationship of these rates to
fundamental molecular parameters. The chapter opens with a
brief discussion of the applications of RET studies to other
areas of science and technology. The study of the
relationship between the intermolecular potential (IMP) and
a wide range of important molecular phenomena is a holy
grail of physical chemistry. Because collisions directly
sample the IMP, a considerable amount of the RET work to
date has been either directly or indirectly motivated by
this quest. Another area in which RET plays a role is that
of laser-isotope separation. Molecular gas lasers are
complex devices and as a result, the large majority have
been discovered rather than invented. Although these lasers
have been extensively studied both experimentally and
theoretically, the models used to describe their molecular
collision dynamics ordinarily have been oversimplified. The
relationship between RET studies and far infrared
(FIR)-laser development is symbiotic, with many of the CO,
laser pump coincidences used in RET studies having
previously been discovered in searches for new FIR lasers.
© 1995 Academic Press, Inc.},
Language = {English},
Doi = {10.1016/S1049-250X(08)60166-4},
Key = {Everitt:1995p6501}
}
@article{fds332004,
Author = {Goyette, TM and Guo, W and De Lucia and FC and Brown, ER and McIntosh, KA and Juvan, K and Swartz, JC and Everitt, HO and Guenther,
BD},
Title = {High resolution sub-millimeter spectroscopy using
mode-locked laser driven electro-optic antennas},
Journal = {Springer Series in Chemical Physics},
Volume = {62},
Number = {62},
Pages = {56},
Year = {1996},
url = {http://dx.doi.org/10.1007/978-3-642-80314-7_23},
Abstract = {We use a mode-locked laser driven electro-optic antenna as a
continuously tunable, high resolution (<1 MHz), high
absolute accuracy (1:107) millimeter/sub-millimeter
spectroscopic source and to investigate laser phase
noise.},
Doi = {10.1007/978-3-642-80314-7_23},
Key = {fds332004}
}
@article{fds349920,
Author = {EVERITT, H},
Title = {THE RESTORATION OF GADS-HILL-CONSERVATORY},
Journal = {Dickensian},
Volume = {92},
Number = {439},
Pages = {151-153},
Year = {1996},
Key = {fds349920}
}
@article{fds342768,
Author = {Everitt, H and Virgin, M},
Title = {Full services network - Operations and management},
Journal = {Noms '96 1996 Ieee Network Operations and Management
Symposium, Vols. 1 4},
Pages = {787-796},
Publisher = {IEEE},
Year = {1996},
Month = {January},
ISBN = {0-7803-2519-2},
Key = {fds342768}
}
@article{Scherer:1999p1552,
Author = {Scherer, A and Doll, T and Yablonovitch, E and Everitt,
Henry O and Higgins, JA},
Title = {Electromagnetic crystal structures, design, synthesis, and
applications},
Journal = {Journal Of Lightwave Technology},
Volume = {17},
Number = {11},
Pages = {1928--1930},
Organization = {CALTECH, Pasadena, CA 91125 USA},
Institution = {CALTECH, Pasadena, CA 91125 USA},
Year = {1999},
Month = {January},
url = {http://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=Papers&UT=000083675100001&SID=2Ccj8oMng2n65nLN754&Init=Yes&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Language = {English},
Key = {Scherer:1999p1552}
}
@article{Bergmann:1999p1549,
Author = {Bergmann, MJ and Özgür, U and Casey, HC and Everitt, HO and Muth,
JF},
Title = {Ordinary and extraordinary refractive indices for
AlxGa1-xN epitaxial
layers},
Journal = {Applied Physics Letters},
Volume = {75},
Number = {1},
Pages = {67-69},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {1999},
Month = {July},
ISSN = {0003-6951},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000081169300023&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {A large variation in the dispersion data for AlxGa1.0-xN
epitaxial layers is presented. An experimental study is
conducted which no(λ) and ne(λ) were measured to an
accuracy of approximately ±0.01 for five AlxGa1.0-xN
MOCVD-grown layers on sapphire substrates with 450<λ<980
nm. The uncertainty in the index of the rutile TiO2 prism
limited the absolute accuracy of the measurements. The
relative accuracy between the dispersion curves is
approximately ±0.0005 and the accuracy of the Al molar
concentration x is ±10%. Simple functions were discussed
that allow convenient calculation of the refractive indices
as functions of x and λ.},
Language = {English},
Doi = {10.1063/1.124278},
Key = {Bergmann:1999p1549}
}
@article{Scherer:1999cf,
Author = {Scherer, A and Doll, T and Yablonovitch, E and Everitt, HO and Higgins,
JA},
Title = {Guest editorial: Electromagnetic crystal structures, design,
synthesis, and applications},
Journal = {Journal of Lightwave Technology},
Volume = {17},
Number = {11},
Pages = {1928-1930},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {November},
ISSN = {0733-8724},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000083675100001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Abstract A new paradigm has emerged in which the band
structure concepts of solid-state physics are applied to
electromagnetics. This has led to a profusion of scientific
creativity as new forms of electromagnetic crystal
structures are invented for radio and microwaves as
...},
Doi = {10.1109/jlt.1999.1673018},
Key = {Scherer:1999cf}
}
@article{Scherer:1999vq,
Author = {Scherer, A and Doll, T and Yablonovitch, E and Everitt, H and Higgins,
A},
Title = {Guest editorial},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {47},
Number = {11},
Pages = {2057-2058},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {CALTECH, Dept Elect Engn, Pasadena, CA 91125
USA},
Institution = {CALTECH, Dept Elect Engn, Pasadena, CA 91125
USA},
Year = {1999},
Month = {November},
ISSN = {0018-9480},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000083406900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Language = {English},
Doi = {10.1109/tmtt.1999.798000},
Key = {Scherer:1999vq}
}
@article{Beaky:1999p1554,
Author = {Beaky, MM and Burk, JB and Everitt, HO and Haider, MA and Venakides,
S},
Title = {Two-dimensional photonic crystal fabry-perot resonators with
lossy dielectrics},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {47},
Number = {11},
Pages = {2085-2091},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {1999},
Month = {December},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=000083406900004&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {Square and triangular lattice two-dimensional (2-D) photonic
crystals (PC's) composed of lossy dielectric rods in air
were constructed with a microwave bandgap between 4-8 GHz.
Fabry-Perot resonators of varying length were constructed
from two of these PC's of adjustable thickness and
reflectivity. The quality factor of cavity modes supported
in the resonators was found to increase with increasing PC
mirror thickness, but only to a point dictated by the
lossiness of the dielectric rods. A 2-D periodic Green's
function simulation was found to model the data accurately
and quickly using physical parameters obtained in separate
measurements. Simple rules are developed for designing
optimal resonators in the presence of dielectric loss. ©
1999 IEEE.},
Language = {English},
Doi = {10.1109/22.798003},
Key = {Beaky:1999p1554}
}
@article{Teng:2000p1539,
Author = {Teng, CW and Muth, JF and Özgür, U and Bergmann, MJ and Everitt, HO and Sharma, AK and Jin, C and Narayan, J},
Title = {Refractive indices and absorption coefficients of
MgxZn1-xO alloys},
Journal = {Applied Physics Letters},
Volume = {76},
Number = {8},
Pages = {979-981},
Publisher = {AIP Publishing},
Organization = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27695 USA},
Institution = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27695 USA},
Year = {2000},
Month = {February},
ISSN = {0003-6951},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=000085343700013&SID=2Dfb9AFL3jni2%40d8oGp&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {Indices of refraction for MgxZn1-xO epitaxial films grown by
pulsed-laser deposition on sapphire substrates with x up to
0.36 were determined in the range of wavelength 457-968 nm
by analysis of optical transmission spectra and
prism-coupled waveguide measurements. The dispersion follows
the first-order Sellmeier dispersion equation. Absorption
coefficients, exciton energy gaps, and binding energies of
MgxZn1-xO alloys were determined by transmission
spectroscopy. The excitonic absorption features were clearly
visible at room temperature despite alloy broadening. These
results provide important information for the design and
modeling of ZnO/MgZnO heterostructure optoelectronic
devices. © 2000 American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.125912},
Key = {Teng:2000p1539}
}
@article{Ozgur:2000p1542,
Author = {Özgür, U and Bergmann, MJ and Casey, HC and Everitt, HO and Abare, AC and Keller, S and DenBaars, SP},
Title = {Ultrafast optical characterization of carrier capture times
in InxGa1-xN multiple quantum
wells},
Journal = {Applied Physics Letters},
Volume = {77},
Number = {1},
Pages = {109-111},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2000},
Month = {July},
ISSN = {0003-6951},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000087889700037&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Subpicosecond wavelength-degenerate differential
transmission optical spectroscopy was used to characterize
the electron capture time in a 10-period InxGa1-xN
multiple-quantum-well (MQW) structure. Photoluminescence and
photoluminescence excitation spectroscopies demonstrated
enhanced MQW emission for injection within ±50 meV of the
barrier energy. Time-resolved differential transmission
measurements for excitation in this region reveal efficient
electron capture in the quantum wells with a time constant
between 310 and 540 fs. A slower exponential relaxation,
with strongly wavelength-dependent subnanosecond decay
constants, is also observed. © 2000 American Institute of
Physics.},
Language = {English},
Doi = {10.1063/1.126893},
Key = {Ozgur:2000p1542}
}
@article{Demers:2001p1383,
Author = {Demers, JR and Goyette, TM and Ferrio, KB and Everitt, HO and Guenther,
BD and DeLucia, FC},
Title = {“Spectral Purity and Sources of Noise in
Femtosecond-Demodulation Terahertz Sources Driven by
Ti:Sapphire Mode-Locked Lasers},
Journal = {Ieee J. Quant Elect},
Volume = {QE37},
Number = {4},
Pages = {595-605},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {Ohio State Univ, Dept Phys, Columbus, OH 43210
USA},
Institution = {Ohio State Univ, Dept Phys, Columbus, OH 43210
USA},
Year = {2001},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=000167766000015&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {Direct measurements of the spectral purity in terahertz
femtosecond-demodulation sources are reported and compared
to theory. Because these sources operate at very high
harmonics (∼102 - 104) of the mode-lock frequency, a high
spectral purity source is very dependent on a low-jitter
femtosecond laser. Conversely, the spectral content of the
terahertz sources provides detailed information about timing
jitter and stringent tests of models used to describe the
jitter. We find that both the behavior of the central core,
and the noise skirts of the power spectrum of our sources,
can be quantitatively related to measured ripple and
continuum amplitude noise on the Ar+ pump laser by use of
modulation theory.},
Language = {English},
Doi = {10.1109/3.914410},
Key = {Demers:2001p1383}
}
@inproceedings{Ozgur:2001p1546,
Author = {Özgür, U and Lee, CW and Everitt, HO},
Title = {Temperature dependence and reflection of coherent acoustic
phonons in InGaN multiple quantum wells},
Journal = {Physica Status Solidi (B) Basic Research},
Volume = {228},
Number = {1},
Pages = {85-89},
Booktitle = {Physica Status Solidi B-Basic Solid State
Physics},
Publisher = {WILEY},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2001},
Month = {January},
url = {http://access.isiproducts.com/custom_images/wok_failed_auth.html},
Abstract = {Sub-picosecond optical pump-probe techniques were used to
generate coherent zone-folded longitudinal acoustic phonons
(ZFLAPs) in an InGaN multiple quantum well structure.
Differential transmission measurements revealed that
carriers injected near the barrier band edge were quickly
captured into the quantum wells and generated strong
coherent ZFLAP oscillations. Differential reflection
measurements were used to explore the acoustic phonon
transport and reflection in the multiple quantum well
structure.},
Language = {English},
Doi = {10.1002/1521-3951(200111)228:1<85::AID-PSSB85>3.3.CO;2-J},
Key = {Ozgur:2001p1546}
}
@article{Ozgur:2000p1779,
Author = {Özgür, U and Lee, CW and Everitt, HO},
Title = {Control of coherent acoustic phonons},
Journal = {Optics and Photonics News},
Volume = {12},
Number = {12},
Pages = {66},
Publisher = {The Optical Society},
Year = {2001},
Month = {January},
url = {http://arxiv.org/abs/cond-mat/0010170v2},
Keywords = {cond-mat.mes-hall, cond-mat.mtrl-sci},
Abstract = {Control behavior of coherent acoustic phonons was studied.
Acoustic phonons in semiconductor multiple quantum wells
(MQW) are expected to have very long coherence times.
Semiconductor MQWs produce zone folding of the acoustic
phonon branch, allowing direct Raman excitation.},
Doi = {10.1364/OPN.12.12.000066},
Key = {Ozgur:2000p1779}
}
@article{Ozgur:2001p1544,
Author = {Ozgür, U and Lee, CW and Everitt, HO},
Title = {Control of coherent acoustic phonons in semiconductor
quantum wells.},
Journal = {Physical Review Letters},
Volume = {86},
Number = {24},
Pages = {5604-5607},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2001},
Month = {June},
ISSN = {0031-9007},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=000169239500050&SID=1Fl3lnGbDBb87AlP9CL&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {Using subpicosecond optical pump-probe techniques, coherent
zone-folded longitudinal acoustic phonons (ZFLAPs) were
investigated in an InGaN multiple quantum well structure. A
two-pump differential transmission technique was used to
generate and control coherent ZFLAP oscillations through the
relative timing and amplitude of the two pump pulses.
Enhancement and suppression of ZFLAP oscillations were
demonstrated, including complete cancellation of generated
acoustic phonons for the first time in any material system.
Coherent control was used to demonstrate that ZFLAPs are
generated differently in InGaN multiple quantum wells than
in GaAs/AlAs superlattices.},
Language = {English},
Doi = {10.1103/physrevlett.86.5604},
Key = {Ozgur:2001p1544}
}
@inproceedings{WebbWood:2001p1541,
Author = {Webb-Wood, G and Özgür, U and Everitt, HO and Yun, F and Morkoç,
H},
Title = {Measurement of AlxGa1-xN Refractive
Indices},
Journal = {Physica Status Solidi (A) Applied Research},
Volume = {188},
Number = {2},
Pages = {793-797},
Booktitle = {Physica Status Solidi A-Applications And Materials
Science},
Publisher = {WILEY-V C H VERLAG GMBH},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2001},
Month = {November},
ISSN = {0031-8965},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000172779700067&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Dispersion of the ordinary and extraordinary indices of
refraction have been measured systematically for wurtzitic
AlxGa1-xN epitaxial layers with 0 ≤ x ≤ 1.0 throughout
the visible wavelength region 457 nm < λ < 800 nm. The
dispersion, measured by a prism coupling waveguide technique
is found to be well described by a first-order Sellmeier
dispersion formula parameterized as functions of x and
λ.},
Language = {English},
Doi = {10.1002/1521-396X(200112)188:2<793::AID-PSSA793>3.0.CO;2-S},
Key = {WebbWood:2001p1541}
}
@article{Ozgur:2001p1545,
Author = {Özgür, U and Webb-Wood, G and Everitt, HO and Yun, F and Morkoç,
H},
Title = {Systematic measurement of AlxGa1-xN
refractive indices},
Journal = {Applied Physics Letters},
Volume = {79},
Number = {25},
Pages = {4103-4105},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2001},
Month = {December},
ISSN = {0003-6951},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000172682300011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Dispersion of the ordinary and extraordinary indices of
refraction have been measured systematically for wurtzitic
AlxGa1-xN epitaxial layers with 0.0≤x≤1.0 throughout the
visible wavelength region. The dispersion, measured by a
prism coupling waveguide technique, is found to be well
described by a Sellmeier relation. Discrepancies among
previous measurements of refractive index dispersion, as a
consequence of different growth conditions and corresponding
band gap bowing parameter, are reconciled when the Sellmeier
relation is parameterized not by x but by band gap energy.
© 2001 American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.1426270},
Key = {Ozgur:2001p1545}
}
@article{Anonymous:2001p763,
Author = {Lee, CW and Everitt, Henry O and Zavada, J and Hommerich,
U},
Title = {Characteristics of visible luminescence of Eu-doped GaN on
Silicon},
Journal = {Manuscript},
Pages = {1--9},
Year = {2002},
Abstract = {We report time-resolved photoluminescence study of Eu-doped
GaN emission in the visible region.},
Key = {Anonymous:2001p763}
}
@article{Ozgur:2002p1776,
Author = {{\"O}zg{\"u}r, {\"U}mit and Everitt, Henry O and Keller,
Stacia and DenBaars, Steven P},
Title = {Stimulated emission and ultrafast carrier relaxation in
InGaN multiple quantum wells},
Journal = {arXiv},
Volume = {cond-mat.mes-hall},
Year = {2002},
Month = {January},
url = {http://arxiv.org/abs/cond-mat/0210343v1},
Keywords = {cond-mat.mes-hall, cond-mat.mtrl-sci},
Abstract = {Stimulated emission (SE) was measured from two InGaN
multiple quantum well (MQW) laser structures with different
In compositions. SE threshold power densities (I_th)
increased with increasing QW depth (x). Time-resolved
differential transmission measurements mapped the carrier
relaxation mechanisms and explained the dependence of I_th
on x. Carriers are captured from the barriers to the QWs in
< 1 ps, while carrier recombination rates increased with
increasing x. For excitation above I_th an additional, fast
relaxation mechanism appears due to the loss of carriers in
the barriers through a cascaded refilling of the QW state
undergoing SE. The increased material inhomogeneity with
increasing x provides additional relaxation channels outside
the cascaded refilling process, removing carriers from the
SE process and increasing I_th.},
Key = {Ozgur:2002p1776}
}
@article{Ozgur:2002p1765,
Author = {{\"O}zg{\"u}r, {\"U}mit and Everitt, Henry
O},
Title = {Ultrafast carrier relaxation in GaN, In_(0.05)Ga_(0.95)N and
an In_(0.05)Ga_(0.95)/In_(0.15)Ga_(0.85)N Multiple Quantum
Well},
Journal = {arXiv},
Volume = {cond-mat.mes-hall},
Year = {2002},
Month = {January},
url = {http://arxiv.org/abs/cond-mat/0210214v1},
Keywords = {cond-mat.mes-hall, cond-mat.mtrl-sci},
Abstract = {Room temperature, wavelength non-degenerate ultrafast
pump/probe measurements were performed on GaN and InGaN
epilayers and an InGaN multiple quantum well structure.
Carrier relaxation dynamics were investigated as a function
of excitation wavelength and intensity. Spectrally-resolved
sub-picosecond relaxation due to carrier redistribution and
QW capture was found to depend sensitively on the wavelength
of pump excitation. Moreover, for pump intensities above a
threshold of 100 microJ/cm2, all samples demonstrated an
additional emission feature arising from stimulated emission
(SE). SE is evidenced as accelerated relaxation (< 10 ps) in
the pump-probe data, fundamentally altering the
re-distribution of carriers. Once SE and carrier
redistribution is completed, a slower relaxation of up to 1
ns for GaN and InGaN epilayers, and 660 ps for the MQW
sample, indicates carrier recombination through spontaneous
emission.},
Key = {Ozgur:2002p1765}
}
@article{fds332000,
Author = {Özgür, U and Neogi, A and Lee, CW and Everitt, HO},
Title = {Coherent acoustic phonons in InGaN multiple quantum
wells},
Journal = {Conference on Quantum Electronics and Laser Science (Qels)
Technical Digest Series},
Volume = {74},
Pages = {218},
Year = {2002},
Month = {January},
Abstract = {Coherent bulk and zone folded longitudinal acoustic phonons
were generated in InGaN MQWs using impulsive optical
techniques. It was observed that the frequency of the
oscillations was changed by the changing quantum well
period. The bulk phonon transport in the MQW region and
reflection from the surface were measured.},
Key = {fds332000}
}
@article{fds332001,
Author = {Neogi, A and Lee, CW and Everitt, HO and Kuroda, T and Tackeuchi, A and Yablonovitch, E},
Title = {Enhancement of spontaneous emission rate by resonant surface
plasmon coupling},
Journal = {Optics and Photonics News},
Volume = {13},
Number = {12},
Pages = {38},
Year = {2002},
Month = {January},
url = {http://dx.doi.org/10.1364/opn.13.12.000038},
Abstract = {The enhancement of spontaneous emission rate by resonant
surface plasmon (SP) coupling was discussed. An
In0.18Ga0.82N/GaN quantum well (QW) was grown by
metal-organic chemical vapor deposition on sapphire
substrate with a GaN buffer layer and an In0.04Ga0.96N
reference layer. The luminescence signal was dispersed in a
single grating monochrometer and detected by a streak camera
with 15-ps temporal resolution. The results showed that the
silver-coated surface exhibited a bi-exponential decay for
emission between 2.61 and 2.94eV.},
Doi = {10.1364/opn.13.12.000038},
Key = {fds332001}
}
@article{fds332002,
Author = {Neogi, A and Lee, CW and Everitt, HO and Kuroda, T and Tackeuchi, A and Yablonovitch, E},
Title = {Enhancement of spontaneous emission rate in nitrides by
resonant surface plasmon coupling},
Journal = {Conference on Quantum Electronics and Laser Science (Qels)
Technical Digest Series},
Volume = {74},
Pages = {258-259},
Year = {2002},
Month = {January},
Abstract = {Spontaneous emission rate in nitrides was enhanced. The
degree of enhancement increased with increasing film
thickness and decreasing GaN cap layer thickness.
Enhancement factors of almost 100 were indicated by
dramatically accelerated TRPL decay at a frequency
corresponding to the SP resonance.},
Key = {fds332002}
}
@inproceedings{Neogi:ea,
Author = {Neogi, A and Lee, C W and Everitt, Henry O and Kuroda, T and Tackeuchi, A and Yablonovitch, E},
Title = {Summaries of Papers Presented at the Quantum Electronics and
Laser Science Conference},
Pages = {258--259},
Booktitle = {QELS-2002},
Publisher = {Opt. Soc. America},
Year = {2002},
Month = {May},
ISBN = {1-55752-707-5},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=1031393},
Doi = {10.1109/QELS.2002.1031393},
Key = {Neogi:ea}
}
@article{2002MNRAS.335..621S,
Author = {Strader, Jay and Everitt, Henry O and Danford,
Stephen},
Title = {Variable stars in the core of the globular cluster
M3},
Journal = {Monthly Notices Of The Royal Astronomical
Society},
Volume = {335},
Number = {3},
Pages = {621--627},
Organization = {Department of Physics, Duke University, Box 90305, Durham,
NC 27708, USA},
Institution = {Department of Physics, Duke University, Box 90305, Durham,
NC 27708, USA},
Year = {2002},
Month = {September},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002MNRAS.335..621S&link_type=ABSTRACT},
Abstract = {We present the results of a survey for variable stars in the
core of the globular cluster M3. Our findings include the
discovery of 11 new or suspected variables, including a
possible W Vir, and the first period determinations for 13
previously known variables.},
Language = {English},
Doi = {10.1046/j.1365-8711.2002.05645.x},
Key = {2002MNRAS.335..621S}
}
@article{Strader:2002p1543,
Author = {Strader, J and Everitt, HO and Danford, S},
Title = {Variable stars in the core of the globular cluster
M3},
Journal = {Monthly Notices of the Royal Astronomical
Society},
Volume = {335},
Number = {3},
Pages = {621-627},
Publisher = {Oxford University Press (OUP)},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2002},
Month = {September},
ISSN = {0035-8711},
url = {http://links.isiglobalnet2.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=mekentosj&SrcApp=Papers&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000178283100016},
Abstract = {We present the results of a survey for variable stars in the
core of the globular cluster M3. Our findings include the
discovery of 11 new or suspected variables, including a
possible W Vir, and the first period determinations for 13
previously known variables.},
Language = {English},
Doi = {10.1046/j.1365-8711.2002.05645.x},
Key = {Strader:2002p1543}
}
@article{2002PhRvB..66o3305N,
Author = {Neogi, A and Lee, CW and Everitt, HO and Kuroda, T and Tackeuchi, A and Yablonovitch, E},
Title = {Enhancement of spontaneous recombination rate in a quantum
well by resonant surface plasmon coupling},
Journal = {Physical Review. B, Condensed Matter},
Volume = {66},
Number = {15},
Pages = {1533051-1533054},
Organization = {Department of Physics, Duke University, Durham, North
Carolina 27708},
Institution = {Department of Physics, Duke University, Durham, North
Carolina 27708},
Year = {2002},
Month = {October},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002PhRvB..66o3305N&link_type=ABSTRACT},
Abstract = {Using time-resolved photoluminescence measurements, the
recombination rate in an In0.18Ga0.82N/GaN quantum well (QW)
is shown to be greatly enhanced when spontaneous emission is
resonantly coupled to a silver surface plasmon. The rate of
enhanced spontaneous emission into the surface plasmon was
as much as 92 times faster than QW spontaneous emission into
free space. A calculation, based on Fermi's golden rule,
reveals that the enhancement is very sensitive to silver
thickness and indicates even greater enhancements are
possible for QW's placed closer to the surface metal
coating.},
Doi = {10.1103/PhysRevB.66.153305},
Key = {2002PhRvB..66o3305N}
}
@article{Ozgur:2003p1280,
Author = {{\"O}zg{\"u}r, Umit and Everitt, HO},
Title = {Ultrafast carrier relaxation in GaN, In0.05Ga0.95N, and an
In0.07Ga0.93N/In0.12Ga0.88N multiple quantum
well},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {67},
Number = {15},
Pages = {--},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2003},
url = {http://prola.aps.org/abstract/PRB/v67/i15/e155308},
Abstract = {Room-temperature, wavelength-nondegenerate ultrafast
pump/probe measurements were performed on GaN and InGaN
epilayers and an InGaN multiple quantum well (QW) structure.
Carrier relaxation dynamics were investigated as a function
of excitation wavelength and intensity. Spectrally resolved
sub-picosecond relaxation due to carrier redistribution and
QW capture was found to depend sensitively on the wavelength
of pump excitation. Moreover, for pump intensities above a
threshold of 100 muJ/cm(2), all samples demonstrated an
additional emission feature arising from stimulated emission
(SE). SE is evidenced as accelerated relaxation (<10 ps) in
the pump-probe data, fundamentally altering the
redistribution of carriers. Once SE and carrier
redistribution is completed, a slower relaxation of up to 1
ns for GaN and InGaN epilayers, and 660 ps for the multiple
QW sample, indicates carrier recombination through
spontaneous emission.},
Language = {English},
Doi = {10.1103/PhysRevB.67.155308},
Key = {Ozgur:2003p1280}
}
@article{fds331999,
Author = {Lee, CW and Everitt, HO and Javada, JM and Steckl,
AJ},
Title = {Temperature dependent visible photoluminescence of Eudoped
GaN on silicon},
Journal = {Osa Trends in Optics and Photonics Series},
Volume = {88},
Pages = {999-1000},
Year = {2003},
Month = {January},
Abstract = {A spectroscopic study of Eu-doped GaN grown on silicon by
solid state molecular beam epitaxy is presented. The
temperature dependence of the continuous-wave and
time-resolved luminescence properties reveals details about
the energy transfer rates and thermal activation energies.
© 2003 Optical Society of America.},
Key = {fds331999}
}
@article{fds365177,
Author = {Neogi, A and Everitt, HO and Morkoç, H and Kuroda, T and Tackeuchi,
A},
Title = {Effects of Strain on Carrier Recombination in GaN Quantum
Dots},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {1557527490},
Abstract = {Strain-induced modification of recombination dynamics in
single layer (SQDs) and stacked (MQDs) GaN quantum dots is
compared by time-resolved photoluminescence spectroscopy.
Large strain induced built-in fields increases the radiative
recombination time in SQDs by over an order of magnitude
while stacking significantly reduces nonradiative
recombination channels and increases the emission efficiency
at room temperature.},
Key = {fds365177}
}
@article{fds365850,
Author = {Lee, CW and Everitt, HO and Javada, JM and Steckl,
AJ},
Title = {Temperature dependent visible photoluminescence of Eu-doped
GaN on Silicon},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {1557527334},
Abstract = {A spectroscopic study of Eu-doped GaN grown on silicon by
solid state molecular beam epitaxy is presented. The
temperature dependence of the continuous-wave and
time-resolved luminescence properties reveals details about
the energy transfer rates and thermal activation
energies.},
Key = {fds365850}
}
@article{Neogi:2003p769,
Author = {Neogi, A and Everitt, H and Morkoç, H and Kuroda, T and Tackeuchi,
A},
Title = {Enhanced radiative efficiency in GaN quantum dots grown by
molecular beam epitaxy},
Journal = {Ieee Transactions on Nanotechnology},
Volume = {2},
Number = {1},
Pages = {10-14},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2003},
Month = {March},
ISSN = {1536-125X},
url = {http://dx.doi.org/10.1109/TNANO.2003.808513},
Abstract = {Self-assembled GaN quantum dots (QDs), grown on AlN by
molecular beam epitaxy, were investigated by time-resolved
photoluminescence spectroscopy. We investigate the emission
mechanism in GaN QDs by comparing the carrier recombination
dynamics in single and multiple period QDs. At 100 K, the PL
decay time in single period QD structures is considerably
shorter than in stacked QDs. Compared to single period QDs,
the room temperature PL efficiency is considerably enhanced
in 20 period QDs due to the reduction in nonradiative
recombination processes.},
Language = {English},
Doi = {10.1109/TNANO.2003.808513},
Key = {Neogi:2003p769}
}
@article{Ozgur:2003p1540,
Author = {Özgür, U and Everitt, HO and Keller, S and DenBaars,
SP},
Title = {Stimulated emission and ultrafast carrier relaxation in
InGaN multiple quantum wells},
Journal = {Applied Physics Letters},
Volume = {82},
Number = {9},
Pages = {1416-1418},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2003},
Month = {March},
ISSN = {0003-6951},
url = {http://link.aip.org/link/APPLAB/v82/i9/p1416/s1&Agg=doi},
Abstract = {A study was performed on ultrafast carrier relaxation and
simulated emission (SE) in InGaN multiple quantum wells
(MQW). Two InGaN MQW laser structures with different QW In
compositions x was used to measure SE. It was found that SE
threshold energy densities (Ith) increased with increasing
x-dependent QW depth.},
Language = {English},
Doi = {10.1063/1.1557770},
Key = {Ozgur:2003p1540}
}
@article{2003PhRvB..67o5308O,
Author = {{\"O}zg{\"u}r, {\"U}mit and Everitt, Henry
O},
Title = {Ultrafast carrier relaxation in GaN, In0.05Ga0.95N, and an
In0.07Ga0.93N/In0.12Ga0.88N multiple quantum
well},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {67},
Number = {15},
Pages = {155308},
Organization = {Department of Physics, Duke University, Durham, North
Carolina 27708},
Institution = {Department of Physics, Duke University, Durham, North
Carolina 27708},
Year = {2003},
Month = {April},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003PhRvB..67o5308O&link_type=ABSTRACT},
Abstract = {Room-temperature, wavelength-nondegenerate ultrafast
pump/probe measurements were performed on GaN and InGaN
epilayers and an InGaN multiple quantum well (QW) structure.
Carrier relaxation dynamics were investigated as a function
of excitation wavelength and intensity. Spectrally resolved
sub-picosecond relaxation due to carrier redistribution and
QW capture was found to depend sensitively on the wavelength
of pump excitation. Moreover, for pump intensities above a
threshold of 100 $\mu$J/cm2, all samples demonstrated an
additional emission feature arising from stimulated emission
(SE). SE is evidenced as accelerated relaxation (<10 ps) in
the pump-probe data, fundamentally altering the
redistribution of carriers. Once SE and carrier
redistribution is completed, a slower relaxation of up to 1
ns for GaN and InGaN epilayers, and 660 ps for the multiple
QW sample, indicates carrier recombination through
spontaneous emission.},
Doi = {10.1103/PhysRevB.67.155308},
Key = {2003PhRvB..67o5308O}
}
@article{fds331998,
Author = {Özgür, U and Everitt, HO},
Title = {Ultrafast carrier relaxation in GaN, In0.05Ga0.95N,
and an In0.07Ga0.93N/In0.12Ga0.88N
multiple quantum well},
Journal = {Physical Review. B, Condensed Matter},
Volume = {67},
Number = {15},
Pages = {1553081-1553089},
Year = {2003},
Month = {April},
Abstract = {Room-temperature, wavelength-nondegenerate ultrafast
pump/probe measurements were performed on GaN and InGaN
epilayers and an InGaN multiple quantum well (QW) structure.
Carrier relaxation dynamics were investigated as a function
of excitation wavelength and intensity. Spectrally resolved
sub-picosecond relaxation due to carrier redistribution and
QW capture was found to depend sensitively on the wavelength
of pump excitation. Moreover, for pump intensities above a
threshold of 100 μJ/cm2, all samples demonstrated an
additional emission feature arising from stimulated emission
(SE). SE is evidenced as accelerated relaxation (< 10 ps) in
the pump-probe data, fundamentally altering the
redistribution of carriers. Once SE and carrier
redistribution is completed, a slower relaxation of up to 1
ns for GaN and InGaN epilayers, and 660 ps for the multiple
QW sample, indicates carrier recombination through
spontaneous emission.},
Key = {fds331998}
}
@article{fds318435,
Author = {Özgür, Ü and Everitt, HO},
Title = {Ultrafast carrier relaxation in GaN, (formula presented) and
an (formula presented) multiple quantum well},
Journal = {Physical Review B},
Volume = {67},
Number = {15},
Publisher = {American Physical Society (APS)},
Year = {2003},
Month = {April},
url = {http://dx.doi.org/10.1103/PhysRevB.67.155308},
Abstract = {Room-temperature, wavelength-nondegenerate ultrafast
pump/probe measurements were performed on GaN and InGaN
epilayers and an InGaN multiple quantum well (QW) structure.
Carrier relaxation dynamics were investigated as a function
of excitation wavelength and intensity. Spectrally resolved
sub-picosecond relaxation due to carrier redistribution and
QW capture was found to depend sensitively on the wavelength
of pump excitation. Moreover, for pump intensities above a
threshold of (formula presented) all samples demonstrated an
additional emission feature arising from stimulated emission
(SE). SE is evidenced as accelerated relaxation (formula
presented) in the pump-probe data, fundamentally altering
the redistribution of carriers. Once SE and carrier
redistribution is completed, a slower relaxation of up to 1
ns for GaN and InGaN epilayers, and 660 ps for the multiple
QW sample, indicates carrier recombination through
spontaneous emission. © 2003 The American Physical
Society.},
Doi = {10.1103/PhysRevB.67.155308},
Key = {fds318435}
}
@article{Ozgur:2003p1288,
Author = {Özgür, U and Everitt, HO and He, L and Morkoç,
H},
Title = {Stimulated emission and ultrafast carrier relaxation in
AlGaN/GaN multiple quantum wells},
Journal = {Applied Physics Letters},
Volume = {82},
Number = {23},
Pages = {4080-4082},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2003},
Month = {June},
ISSN = {0003-6951},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000082000023004080000001&idtype=cvips&gifs=yes},
Abstract = {The stimulated emission and ultrafast carrier relaxation in
AlGaN/GaN multiple quantum wells were analyzed. The room
temperature, time-resolved, differential transmission
measurements were used to map the carrier relaxation
mechanism for above barrier energy excitation. The
photoexcited carriers were observed to relax into the
quantum wells in less than 1ps while the carrier
recombination times were found to be as fast as
30ps.},
Language = {English},
Doi = {10.1063/1.1581385},
Key = {Ozgur:2003p1288}
}
@article{fds331997,
Author = {Neogi, A and Everitt, HO and Morkoç, H and Kuroda, T and Tackeuchi,
A},
Title = {Effects of strain on carrier recombination in GaN quantum
dots},
Journal = {Conference on Quantum Electronics and Laser Science (Qels)
Technical Digest Series},
Volume = {89},
Year = {2003},
Month = {December},
Abstract = {Strain-induced modification of recombination dynamics in
single layer (SQDs) and stacked (MQDs) GaN quantum dots is
compared by time-resolved photoluminescence spectroscopy.
Large strain induced built-in fields increases the radiative
recombination time in SQDs by over an order of magnitude
while stacking significantly reduces nonradiative
recombination channels and increases the emission efficiency
at room temperature.},
Key = {fds331997}
}
@article{Teke:2004p1284,
Author = {Teke, A and {\"O}zg{\"u}r, Umit and Do{\u g}an, S and Gu, X and Morko{\c c}, H and Nemeth, B and Nause, JE and Everitt,
HO},
Title = {Excitonic fine structure and recombination dynamics in
single-crystalline ZnO},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {70},
Number = {19},
Pages = {--},
Organization = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Year = {2004},
url = {http://prola.aps.org/abstract/PRB/v70/i19/e195207},
Abstract = {The optical properties of a high quality bulk ZnO, thermally
post treated in a forming gas environment are investigated
by temperature dependent continuous wave and time-resolved
photoluminescence (PL) measurements. Several bound and free
exciton transitions along with their first excited states
have been observed at low temperatures, with the main
neutral-donor-bound exciton peak at 3.3605 eV having a
linewidth of 0.7 meV and dominating the PL spectrum at 10 K.
This bound exciton transition was visible only below 150 K,
whereas the A-free exciton transition at 3.3771 eV persisted
up to room temperature. A-free exciton binding energy of 60
meV is obtained from the position of the excited states of
the free excitons. Additional intrinsic and extrinsic fine
structures such as polariton, two-electron satellites,
donor-acceptor pair transitions, and longitudinal
optical-phonon replicas have also been observed and
investigated in detail. Time-resolved PL measurements at
room temperature reveal a biexponential decay behavior with
typical decay constants of similar to170 and similar to864
ps for the as-grown sample. Thermal treatment is observed to
increase the carrier lifetimes when performed in a forming
gas environment.},
Language = {English},
Doi = {10.1103/PhysRevB.70.195207},
Key = {Teke:2004p1284}
}
@article{Everitt:2004p423,
Author = {Everitt, Henry O},
Title = {Special Issue on Experimental Aspects of Quantum Computing:
Introduction},
Journal = {Quantum Information Processing},
Year = {2004},
Month = {January},
url = {http://www.springerlink.com/index/X4737V1W672N1178.pdf},
Abstract = {Page 1. Quantum Information Processing, Vol. 3, Nos. 1--5,
October 2004 ({\copyright} 2004) INTRODUCTION},
Key = {Everitt:2004p423}
}
@article{Ozgur:2004p1282,
Author = {Özgür, U and Teke, A and Liu, C and Cho, SJ and Morkoç, H and Everitt,
HO},
Title = {Stimulated emission and time-resolved photoluminescence in
rf-sputtered ZnO thin films},
Journal = {Applied Physics Letters},
Volume = {84},
Number = {17},
Pages = {3223-3225},
Publisher = {AIP Publishing},
Organization = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Year = {2004},
Month = {April},
ISSN = {0003-6951},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000084000017003223000001&idtype=cvips&gifs=yes},
Abstract = {A measurement of stimulated emission (SE) from ZnO thin
films grown on c-plane sapphire by rf sputtering was
performed. At 10 K, free exciton transitions were observed
in the photoluminescence (PL), transmission and reflection
spectra of the sample annealed at 950°C. SE resulting from
both electron hole plasma formation and exciton-exciton
scattering was observed at moderate excitation energy
densities in the annealed samples. The observation of low
threshold exciton-exciton scattering-induced SE showed that
in rf-sputtered ZnO thin films, excitonic laser action could
be obtained.},
Language = {English},
Doi = {10.1063/1.1713034},
Key = {Ozgur:2004p1282}
}
@article{Lee:2004p834,
Author = {Lee, CW and Everitt, HO and Lee, DS and Steckl, AJ and Zavada,
JM},
Title = {Temperature dependence of energy transfer mechanisms in
Eu-doped GaN},
Journal = {Journal of Applied Physics},
Volume = {95},
Number = {12},
Pages = {7717-7724},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2004},
Month = {June},
ISSN = {0021-8979},
url = {http://links.isiglobalnet2.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=mekentosj&SrcApp=Papers&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000221843400025},
Abstract = {Time-resolved photoluminescence measurements of the 5D 0→
7F 2 and 5G 0→ 7F 3 transitions were performed for
investigating the temperature-dependent energy transfer
mechanisms of Eu-doped GaN. Numerically integrated rate
equation models enabled the analysis of the luminescence
decay. A nonlinear least-squares technique was used to fit
the model predictions to the data in order to extract the
decay constants. The 5D 0 state exhibited a radiative decay
rate which was measured to be 166 μs.},
Language = {English},
Doi = {10.1063/1.1738529},
Key = {Lee:2004p834}
}
@article{2004SPIE.5352..158O,
Author = {Özgür, U and Everitt, HO and Keller, S and DenBaars, SP and He, L and Morkoç, H},
Title = {Ultrafast carrier relaxation in group III-nitride multiple
quantum wells},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {5352},
Pages = {158-168},
Publisher = {SPIE},
Organization = {Virginia Commonwealth Univ. (USA)},
Institution = {Virginia Commonwealth Univ. (USA)},
Year = {2004},
Month = {August},
ISBN = {0-8194-5260-2},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000222660600016&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In this study, stimulated emission (SE) and ultrafast
carrier relaxation are explored in InGaN and AlGaN/GaN
multiple quantum wells (MQWs). The SE threshold densities (I
th) in InGaN MQWs increase with increasing QW depth. By
contrast, no significant variation is observed in AlGaN/GaN
MQWs with varying barrier height and growth conditions
(Ga-rich or N-rich). Wavelength non-degenerate time-resolved
differential transmission (TRDT) measurements reveal that
increased non-radiative recombination and fast capture of
carriers to the localized states below the SE energy in
deeper InGaN MQWs are responsible for the increased I th. At
high excitation densities SE is shown to remove carriers
efficiently from the QWs with a time constant of a few
picoseconds, causing carriers at higher energies to cascade
down and refill these SE-emptied states. The strength and
decay times of the SE feature, which are resolved from the
spectrally integrated TRDT data, are seen to vary as a
function of excitation energy and density. The fast,
SE-accelerated decay in AlGaN MQWs occurs more than twice as
fast as in InGaN MQWs for similar excitation densities. More
importantly, recombination times are an order of magnitude
faster in AlGaN MQWs than in InGaN MQWs.},
Doi = {10.1117/12.529426},
Key = {2004SPIE.5352..158O}
}
@article{fds314106,
Author = {Everitt, H},
Title = {Special issue on experimental aspects of quantum
computing},
Journal = {Quantum Information Processing},
Volume = {3},
Number = {1-5},
Pages = {1-4},
Publisher = {Springer Nature},
Year = {2004},
Month = {October},
ISSN = {1570-0755},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000208503100001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Doi = {10.1007/s11128-004-9416-4},
Key = {fds314106}
}
@article{2004PhRvB..70s5207T,
Author = {Teke, A and {\"O}zg{\"u}r, {\"U}mit and Do{\u g}an, S and Gu, X and Morko{\c c}, H and Nemeth, B and Nause, J and Everitt, Henry O},
Title = {Excitonic fine structure and recombination dynamics in
single-crystalline ZnO},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {70},
Number = {19},
Pages = {195207},
Organization = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284, USA},
Institution = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284, USA},
Year = {2004},
Month = {November},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004PhRvB..70s5207T&link_type=ABSTRACT},
Abstract = {The optical properties of a high quality bulk ZnO ,
thermally post treated in a forming gas environment are
investigated by temperature dependent continuous wave and
time-resolved photoluminescence (PL) measurements. Several
bound and free exciton transitions along with their first
excited states have been observed at low temperatures, with
the main neutral-donor-bound exciton peak at 3.3605eV having
a linewidth of 0.7meV and dominating the PL spectrum at 10K
. This bound exciton transition was visible only below 150K
, whereas the A-free exciton transition at 3.3771eV
persisted up to room temperature. A-free exciton binding
energy of 60meV is obtained from the position of the excited
states of the free excitons. Additional intrinsic and
extrinsic fine structures such as polariton, two-electron
satellites, donor-acceptor pair transitions, and
longitudinal optical-phonon replicas have also been observed
and investigated in detail. Time-resolved PL measurements at
room temperature reveal a biexponential decay behavior with
typical decay constants of ˜170 and ˜864ps for the
as-grown sample. Thermal treatment is observed to increase
the carrier lifetimes when performed in a forming gas
environment.},
Doi = {10.1103/PhysRevB.70.195207},
Key = {2004PhRvB..70s5207T}
}
@article{fds314065,
Author = {Teke, A and Özgür, U and Doǧan, S and Gu, X and Morkoç, H and Nemeth,
B and Nause, J and Everitt, HO},
Title = {Excitonic fine structure and recombination dynamics in
single-crystalline ZnO},
Journal = {Physical Review. B, Condensed Matter},
Volume = {70},
Number = {19},
Pages = {1-10},
Publisher = {American Physical Society (APS)},
Year = {2004},
Month = {November},
ISSN = {1098-0121},
url = {http://dx.doi.org/10.1103/PhysRevB.70.195207},
Abstract = {The optical properties of a high quality bulk ZnO, thermally
post treated in a forming gas environment are investigated
by temperature dependent continuous wave and time-resolved
photoluminescence (PL) measurements. Several bound and free
exciton transitions along with their first excited states
have been observed at low temperatures, with the main
neutral-donor-bound exciton peak at 3.3605 eV having a
linewidth of 0.7 meV and dominating the PL spectrum at 10 K.
This bound exciton transition was visible only below 150 K,
whereas the A-free exciton transition at 3.3771 eV persisted
up to room temperature. A-free exciton binding energy of 60
meV is obtained from the position of the excited states of
the free excitons. Additional intrinsic and extrinsic fine
structures such as polariton, two-electron satellites,
donor-acceptor pair transitions, and longitudinal
optical-phonon replicas have also been observed and
investigated in detail. Time-resolved PL measurements at
room temperature reveal a biexponential decay behavior with
typical decay constants of ∼170 and ∼864 ps for the
as-grown sample. Thermal treatment is observed to increase
the carrier lifetimes when performed in a forming gas
environment.},
Doi = {10.1103/PhysRevB.70.195207},
Key = {fds314065}
}
@article{Peng:2005p1283,
Author = {Peng, HY and Lee, CW and Everitt, HO and Lee, DS and Steckl,
AJ and Zavada, JM},
Title = {Effect of optical excitation energy on the red luminescence
of Eu3+ in GaN},
Journal = {Applied Physics Letters},
Volume = {86},
Number = {5},
Pages = {--},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2005},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000086000005051110000001&idtype=cvips&gifs=yes},
Abstract = {Photoluminescence (PL) excitation spectroscopy mapped the
photoexcitation wavelength dependence of the red
luminescence (D-5(0) --> F-7(2)) from GaN:Eu. Time-resolved
PL measurements revealed that for excitation at the GaN
bound exciton energy, the decay transients are almost
temperature insensitive between 86 K and 300 K, indicating
an efficient energy transfer process. However, for
excitation energies above or below the GaN bound exciton
energy, the decaying luminescence indicates excitation
wavelength- and temperature-dependent energy transfer
influenced by intrinsic and Eu3+-related defects. (C) 2005
American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.1861132},
Key = {Peng:2005p1283}
}
@book{Everitt:2005tm,
Author = {Everitt, Henry O},
Title = {Experimental aspects of quantum computing - Henry O. Everitt
- Google Books},
Publisher = {Springer},
Year = {2005},
url = {http://books.google.com/books?hl=en&lr=&id=bw1P7jZ_-ewC&oi=fnd&pg=PA1&dq=henry+everitt&ots=8BXaiaVjdP&sig=trKKcvpsayYdEo0r-_ijPeGSfbs},
Abstract = {Practical quantum computing still seems more than a decade
away, and researchers have not even identified what the best
physical implementation of a quantum bit will be. There is a
real need in the scientific literature for a dialogue on the
topic of lessons learned and ...},
Key = {Everitt:2005tm}
}
@article{fds318431,
Author = {Munasinghe, C and Steckl, A and Nyein, EE and Hömmerich, U and Peng, H and Everitt, H and Fleischman, Z and Dierolf, V and Zavada,
J},
Title = {GaN:Eu interrupted growth epitaxy (IGE): Thin film growth
and electroluminescent devices},
Journal = {Materials Research Society Symposium Proceedings},
Volume = {866},
Pages = {41-52},
Year = {2005},
Month = {January},
ISBN = {1-55899-819-5},
url = {http://dx.doi.org/10.1557/proc-866-v3.1},
Abstract = {The GaN:RE phosphor development plays a major role in the
GaN:RE AC thick dielectric electroluminescent (TDEL) device
optimization. In this paper we report on EL devices
fabricated using Eu-doped GaN red phosphors films grown by
interrupted growth epitaxy (IGE). IGE consists of a sequence
of ON/OFF cycles of the Ga and Eu beams, while the N2 plasma
is kept constant during the entire growth time. IGE growth
of GaN:Eu resulted in significant enhancement in the Eu
emission intensity based primarily at 620.5nm. The increase
in the material crystallinity observed with the IGE
phosphors appears to be the dominant cause of the emission
enhancement. Thick dielectric EL devices fabricated on glass
substrates using IGE-grown GaN:Eu have resulted in luminance
of ∼ 1000 cd/m2. © 2005 Materials Research
Society.},
Doi = {10.1557/proc-866-v3.1},
Key = {fds318431}
}
@article{fds331995,
Author = {Foreman, JV and Peng, H and Choi, S and Everitt, HO and Li, J and Liu,
J},
Title = {Bright, eye-matched visible emission from ZnO
nanowires},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {Broadband, visible-wavelength emission of unprecedented
brightness from ZnO nanowires is characterized by
steady-state and ultrafast time-resolved spectroscopy.
Energy transfer is explored by simultaneously studying the
unusually fast decay of band edge emission. © 2005 Optical
Society of America.},
Key = {fds331995}
}
@article{fds331996,
Author = {Peng, HY and Everitt, HO and Munasinghe, C and Lee, DS and Steckl,
AJ},
Title = {Relaxation dynamics in rare earth-doped GaN},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
Abstract = {Time-resolved photoluminescence spectroscopy of rare earth
(Eu, Er, Tm) -doped GaN revealed that optical properties and
relaxation dynamics depend surprisingly upon excitation
energy, pulse width, temperature, and dopant site. © 2005
Optical Society of America.},
Key = {fds331996}
}
@article{fds350129,
Author = {Foreman, JV and Peng, H and Choi, S and Everitt, HO and Li, J and Liu,
J},
Title = {Bright, eye-matched visible emission from ZnO
nanowires},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
url = {http://dx.doi.org/10.1364/fio.2005.ftuf4},
Abstract = {Broadband, visible-wavelength emission of unprecedented
brightness from ZnO nanowires is characterized by
steady-state and ultrafast time-resolved spectroscopy.
Energy transfer is explored by simultaneously studying the
unusually fast decay of band edge emission. © 2005 Optical
Society of America.},
Doi = {10.1364/fio.2005.ftuf4},
Key = {fds350129}
}
@article{fds351269,
Author = {Peng, HY and Everitt, HO and Munasinghe, C and Lee, DS and Steckl,
AJ},
Title = {Relaxation dynamics in rare earth-doped GaN},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
url = {http://dx.doi.org/10.1364/fio.2005.ftuf2},
Abstract = {Time-resolved photoluminescence spectroscopy of rare earth
(Eu, Er, Tm) -doped GaN revealed that optical properties and
relaxation dynamics depend surprisingly upon excitation
energy, pulse width, temperature, and dopant site. © 2005
Optical Society of America.},
Doi = {10.1364/fio.2005.ftuf2},
Key = {fds351269}
}
@article{2005ApPhL..86e1110P,
Author = {Peng, HY and Lee, CW and Everitt, HO and Lee, DS and Steckl, AJ and Zavada,
JM},
Title = {Effect of optical excitation energy on the red luminescence
of Eu3+ in GaN},
Journal = {Applied Physics Letters},
Volume = {86},
Number = {5},
Pages = {1-3},
Publisher = {AIP Publishing},
Organization = {Department of Physics, Duke University, Durham, North
Carolina 27708},
Institution = {Department of Physics, Duke University, Durham, North
Carolina 27708},
Year = {2005},
Month = {January},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005ApPhL..86e1110P&link_type=ABSTRACT},
Abstract = {Photoluminescence (PL) excitation spectroscopy mapped the
photoexcitation wavelength dependence of the red
luminescence (D05 → F27) from GaN:Eu. Time-resolved PL
measurements revealed that for excitation at the GaN bound
exciton energy, the decay transients are almost temperature
insensitive between 86 K and 300 K, indicating an efficient
energy transfer process. However, for excitation energies
above or below the GaN bound exciton energy, the decaying
luminescence indicates excitation wavelength- and
temperature-dependent energy transfer influenced by
intrinsic and Eu3+ -related defects. © 2005 American
Institute of Physics.},
Doi = {10.1063/1.1861132},
Key = {2005ApPhL..86e1110P}
}
@article{2005ApPhL..86l1906C,
Author = {Cook, B P and Everitt, Henry O and Avrutsky, I and Osinsky,
A and Cai, A and Muth, John F},
Title = {Refractive indices of ZnSiN2 on r-plane sapphire},
Journal = {Applied Physics Letters},
Volume = {86},
Number = {12},
Pages = {1906},
Organization = {Department of Mathematics, University of California, Los
Angeles, Los Angeles, California 90095},
Institution = {Department of Mathematics, University of California, Los
Angeles, Los Angeles, California 90095},
Year = {2005},
Month = {March},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005ApPhL..86l1906C&link_type=ABSTRACT},
Abstract = {II-IV-N2 wide band gap semiconductors such as ZnSiN2,
ZnGeN2, and ZnSiGeN2 have potential uses for nonlinear
materials and as lattice matching compounds for the growth
of SiC and GaN devices. In this study, the dispersion of the
TE and TM indices of refraction has been measured
systematically using the prism coupling technique for an
orthorhombic ZnSiN2 epitaxial layer grown on r-plane
sapphire. The resulting index dispersion is extracted from
the measured optical modes using a layered biaxial waveguide
analysis, which shows that although the ZnSiN2 crystal is
orthorhombic, for practical purposes it can be treated as a
uniaxial material.},
Doi = {10.1063/1.1865325},
Key = {2005ApPhL..86l1906C}
}
@article{Neogi:2005p5685,
Author = {Neogi, A and Everitt, H and Morkoç, H and Kuroda, T and Tackeuchi,
A},
Title = {Size dependence of carrier recombination efficiency in GaN
quantum dots},
Journal = {Ieee Transactions on Nanotechnology},
Volume = {4},
Number = {2},
Pages = {297-299},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {Univ N Texas, Dept Phys, Denton, TX 76203
USA},
Institution = {Univ N Texas, Dept Phys, Denton, TX 76203
USA},
Year = {2005},
Month = {March},
url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1406009&tag=1},
Abstract = {The dependence of radiative recombination rate and
efficiency on GaN quantum-dot (QD) size and temperature is
studied by time-resolved photoluminescence (PL)
spectroscopy. The emission is dominated by radiative
recombination at low temperatures (<125 K) and exhibits high
PL efficiency at room temperature. The radiative lifetime
and the relative quantum efficiency decrease with the
decreasing QD size. © 2005 IEEE.},
Language = {English},
Doi = {10.1109/TNANO.2004.834170},
Key = {Neogi:2005p5685}
}
@article{Cook:2005p1287,
Author = {Cook, BP and Everitt, HO and Avrutsky, I and Osinsky, A and Cai, A and Muth, JF},
Title = {Refractive indices of ZnSiN 2 on r-plane
sapphire},
Journal = {Applied Physics Letters},
Volume = {86},
Number = {12},
Pages = {1-3},
Publisher = {AIP Publishing},
Organization = {Univ Calif Los Angeles, Dept Math, Los Angeles, CA 90095
USA},
Institution = {Univ Calif Los Angeles, Dept Math, Los Angeles, CA 90095
USA},
Year = {2005},
Month = {March},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000086000012121906000001&idtype=cvips&gifs=yes},
Abstract = {II-IV- N2 wide band gap semiconductors such as ZnSi N2, ZnGe
N2, and ZnSiGe N2 have potential uses for nonlinear
materials and as lattice matching compounds for the growth
of SiC and GaN devices. In this study, the dispersion of the
TE and TM indices of refraction has been measured
systematically using the prism coupling technique for an
orthorhombic ZnSi N2 epitaxial layer grown on r -plane
sapphire. The resulting index dispersion is extracted from
the measured optical modes using a layered biaxial waveguide
analysis, which shows that although the ZnSi N2 crystal is
orthorhombic, for practical purposes it can be treated as a
uniaxial material. © 2005 American Institute of
Physics.},
Language = {English},
Doi = {10.1063/1.1865325},
Key = {Cook:2005p1287}
}
@article{Ozgur:2005p1281,
Author = {Özgür, U and Fu, Y and Moon, YT and Yun, F and Morko̧, H and Everitt,
HO},
Title = {Increased carrier lifetimes in GaN epitaxial films grown
using SiN and TiN porous network layers},
Journal = {Journal of Applied Physics},
Volume = {97},
Number = {10},
Pages = {103704-103704},
Publisher = {AIP Publishing},
Organization = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Year = {2005},
Month = {May},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JAPIAU000097000010103704000001&idtype=cvips&gifs=yes},
Abstract = {Improved structural quality and radiative efficiency were
observed in GaN thin films grown by metalorganic chemical
vapor deposition on SiN and TiN porous network templates.
The room-temperature decay times obtained from biexponential
fits to time-resolved photoluminescence data are increased
with the inclusion of SiN and TiN layers. The carrier
lifetime of 1.86 ns measured for a TiN network sample is
slightly longer than that for a 200 μm -thick high-quality
freestanding GaN. The linewidth of the asymmetric x-ray
diffraction (XRD) (10 1- 2) peak decreases considerably with
the use of SiN and TiN layers, indicating the reduction in
threading dislocation density. However, no direct
correlation is yet found between the decay times and the XRD
linewidths, suggesting that point defect and
impurity-related nonradiative centers are the main
parameters affecting the lifetime. © 2005 American
Institute of Physics.},
Language = {English},
Doi = {10.1063/1.1894583},
Key = {Ozgur:2005p1281}
}
@article{2005ApPhL..86w2106O,
Author = {{\"O}zg{\"u}r, {\"U}mit and Fu, Y and Moon, Y. T. and Yun, F and Morko{\c c}, H and Everitt, Henry O and Park, S S and Lee, K Y},
Title = {Long carrier lifetimes in GaN epitaxial layers grown using
TiN porous network templates},
Journal = {Applied Physics Letters},
Volume = {86},
Number = {23},
Pages = {2106},
Organization = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284},
Institution = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284},
Year = {2005},
Month = {June},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005ApPhL..86w2106O&link_type=ABSTRACT},
Abstract = {Improved structural quality and radiative efficiency were
observed in GaN thin films grown by metalorganic chemical
vapor deposition on TiN porous network templates formed by
in situ thermal annealing of Ti in ammonia. The
room-temperature decay times obtained from biexponential
fits to time-resolved photoluminescence data are longer than
ever reported for GaN. The carrier lifetime of 1.86 ns
measured for a TiN network sample is slightly longer than
that for a 200 $\mu$m thick high-quality freestanding GaN.
The linewidth of the asymmetric x-ray diffraction (XRD)
(1012) peak decreases considerably with the use of TiN layer
and with increasing in situ annealing time, indicating the
reduction in threading dislocation density. However, no
direct correlation is yet found between the decay times and
the XRD linewidths, suggesting that point defect and
impurity related nonradiative centers are the main
parameters affecting the lifetime.},
Doi = {10.1063/1.1944903},
Key = {2005ApPhL..86w2106O}
}
@article{Ozgur:2005p1286,
Author = {Özgür, U and Fu, Y and Moon, YT and Yun, F and Morko̧, H and Everitt,
HO and Park, SS and Lee, KY},
Title = {Long carrier lifetimes in GaN epitaxial layers grown using
TiN porous network templates},
Journal = {Applied Physics Letters},
Volume = {86},
Number = {23},
Pages = {1-3},
Publisher = {AIP Publishing},
Organization = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Year = {2005},
Month = {June},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000086000023232106000001&idtype=cvips&gifs=yes},
Abstract = {Improved structural quality and radiative efficiency were
observed in GaN thin films grown by metalorganic chemical
vapor deposition on TiN porous network templates formed by
in situ thermal annealing of Ti in ammonia. The
room-temperature decay times obtained from biexponential
fits to time-resolved photoluminescence data are longer than
ever reported for GaN. The carrier lifetime of 1.86 ns
measured for a TiN network sample is slightly longer than
that for a 200 μm thick high-quality freestanding GaN. The
linewidth of the asymmetric x-ray diffraction (XRD) (10 1-
2) peak decreases considerably with the use of TiN layer and
with increasing in situ annealing time, indicating the
reduction in threading dislocation density. However, no
direct correlation is yet found between the decay times and
the XRD linewidths, suggesting that point defect and
impurity related nonradiative centers are the main
parameters affecting the lifetime. © 2005 American
Institute of Physics.},
Language = {English},
Doi = {10.1063/1.1944903},
Key = {Ozgur:2005p1286}
}
@article{Tsen:2005p1285,
Author = {Tsen, KT and Liang, W and Ferry, DK and Lu, H and Schaff, WJ and Ozgur, U and Fu, Y and Moon, YT and Yun, F and Morkoç, H and Everitt,
HO},
Title = {Optical studies of carrier dynamics and non-equilibrium
optical phonons in nitride-based wide bandgap
semiconductors},
Journal = {Superlattices and Microstructures},
Volume = {38},
Number = {2},
Pages = {77-114},
Publisher = {Elsevier BV},
Organization = {Arizona State Univ, Dept Phys {\&} Astron, Tempe, AZ 85287
USA},
Institution = {Arizona State Univ, Dept Phys {\&} Astron, Tempe, AZ 85287
USA},
Year = {2005},
Month = {August},
url = {http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WXB-4GKWHXN-1&_user=961261&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000049394&_version=1&_urlVersion=0&_userid=961261&md5=268afb4095054fab46874f095c57c9c8},
Abstract = {Ultrafast optical probes, photoluminescence spectroscopy,
and Raman spectroscopy have been applied to investigate
carrier dynamics in nitride-based binary and ternary, and
dilute nitride semiconductors. Carrier dynamics in the form
of radiative and non-radiative lifetimes in GaN grown on
pseudo-in situ TiN and in situ SiN nanonetworks by
organometallic vapor phase epitaxy have been investigated
and compared with those for freestanding GaN templates which
constitute the benchmark values due to the high quality.
Room temperature carrier lifetimes as long as 1.86 ns could
be achieved with the use of TiN network templates.
Time-resolved Raman spectroscopy has been employed to
investigate the carrier dynamics, carrier transport and
non-equilibrium optical phonons in In-containing
nitride-based semiconductors. (1) It has been found that the
energy loss rate in InxGa1-xAs 1-yNy is about 64 meV/ps
suggesting that hot electrons lose their energy primarily to
the GaAs-like LO phonons in this dilute nitride
semiconductor. (2) Both the non-equilibrium electron
distribution and the electron drift velocity in InGaN and
InN have been measured. These experimental results are
compared with ensemble Monte Carlo calculations and good
agreement is found. (3) Our experimental results support the
small bandgap value for InN (approximately 0.8 eV) and are
inconsistent with the 0.8 eV luminescence emission being due
to deep level radiative emission. © 2005 Elsevier Ltd. All
rights reserved.},
Language = {English},
Doi = {10.1016/j.spmi.2005.04.004},
Key = {Tsen:2005p1285}
}
@article{fds318432,
Author = {Muth, J and Cai, A and Osinsky, A and Everitt, H and Cook, B and Avrutsky,
I},
Title = {Optical properties of II-IV-N2 semiconductors},
Journal = {Materials Research Society Symposium Proceedings},
Volume = {831},
Pages = {745-749},
Year = {2005},
Month = {August},
ISBN = {1-55899-779-2},
Abstract = {Recently, wide band gap II-IV-N 2 semiconductors such as
ZnSiN 2, and ZnGeN 2 and ZnSiGeN 2 have been synthesized,
but very little is known about their band structure, optical
properties, or electronic properties. Bulk crystals are hard
to synthesize because high temperatures and pressures are
required. The success in growing II-IV-N 2 films epitaxially
by MOCVD creates interesting opportunities. The crystal
structure of II-IV-N 2 compounds is orthorhombic, and when
grown on r-plane sapphire can provide a suitable template
for GaN growth. Optical transmission studies of the band
edge of ZnSiN 2 and ZnSiGeN 2 with varying Si and Ge
percentages were conducted. The indirect nature of the band
gap was investigated, and prism coupling was used to obtain
the refractive indices in the visible and NIR portion of the
spectrum. Although the crystal symmetry was orthorhombic,
the refractive indices indicated uniaxial optical
properties. Optical loss measurements indicate that the
films are suitable for waveguides and novel devices based on
birefringent optical effects. © 2005 Materials Research
Society.},
Key = {fds318432}
}
@article{Ozgur:2006p1276,
Author = {{\"O}zg{\"u}r, {\"U}mit and Gu, X and Chevtchenko, S and Spradlin, J and Cho, SJ and Morkoc, H and Pollak, FH and Everitt, HO and Nemeth, B and Nause, JE},
Title = {Thermal conductivity of bulk ZnO after different thermal
treatments},
Journal = {Journal Of Electronic Materials},
Volume = {35},
Number = {4},
Pages = {550--555},
Organization = {Virginia Commonwealth Univ, Dept Elect {\&} Comp Engn,
Richmond, VA 23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect {\&} Comp Engn,
Richmond, VA 23284 USA},
Year = {2006},
Month = {January},
Abstract = {Thermal conductivities (kappa) of melt-grown bulk ZnO
samples thermally treated under different conditions were
measured using scanning thermal microscopy. Samples annealed
in air at 1050 degrees C for 3 h and treated with N-plasma
at 750 degrees C for 1 min. exhibited kappa = 1.35 +/- 0.08
W/cm-K and kappa = 1.47 +/- 0.08 W/cm-K, respectively. These
are the highest values reported for ZnO. Atomic force
microscopy (AFM) and conductive-AFM measurements revealed
that surface carrier concentration as well as surface
morphology affected the thermal conductivity.},
Language = {English},
Key = {Ozgur:2006p1276}
}
@article{2006JEMat..35..550O,
Author = {{\"O}zg{\"u}r, {\"U}mit and Gu, X and Chevtchenko, S and Spradlin, J and Cho, S-J and Morko{\c c}, H and Pollak, F H and Everitt, Henry O and Nemeth, B and Nause, J
E},
Title = {Thermal conductivity of bulk ZnO after different thermal
treatments},
Journal = {Journal Of Electronic Materials},
Volume = {35},
Number = {4},
Pages = {550--555},
Organization = {Department of Electrical and Computer Engineering, Virginia
Commonwealth University},
Institution = {Department of Electrical and Computer Engineering, Virginia
Commonwealth University},
Year = {2006},
Month = {January},
url = {http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=000237101800009&SID=4FnIC7F76BnjjOEmGgG&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%3A%2F%2Faccess.isiproducts.com%2Fcustom_images%2Fwok_failed_auth.html},
Abstract = {Thermal conductivities (kappa) of melt-grown bulk ZnO
samples thermally treated under different conditions were
measured using scanning thermal microscopy. Samples annealed
in air at 1050 degrees C for 3 h and treated with N-plasma
at 750 degrees C for 1 min. exhibited kappa = 1.35 +/- 0.08
W/cm-K and kappa = 1.47 +/- 0.08 W/cm-K, respectively. These
are the highest values reported for ZnO. Atomic force
microscopy (AFM) and conductive-AFM measurements revealed
that surface carrier concentration as well as surface
morphology affected the thermal conductivity.},
Language = {English},
Doi = {10.1007/s11664-006-0098-9},
Key = {2006JEMat..35..550O}
}
@article{Ozgur:2006bk,
Author = {Özgür, U and Litton, CW and Fu, Y and Moon, YT and Yun, F and Everitt,
HO and Morkoç, H},
Title = {Improved structural quality and carrier decay times in GaN
epitaxy on SiN and TiN porous network templates},
Journal = {Materials Science Forum},
Volume = {527-529},
Number = {PART 2},
Pages = {1505-1508},
Year = {2006},
Month = {January},
ISBN = {9780878494255},
ISSN = {0255-5476},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000244227200356&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Improved structural quality and radiative efficiency were
observed in GaN thin films grown by metalorganic chemical
vapor deposition on in situ-formed SiN and TiN porous
network templates. The room temperature carrier decay time
of 1.86 ns measured for a TiN network sample is slightly
longer than that for a 200 μn-thick high quality
freestanding GaN (1.73 ns). The linewidth of the asymmetric
X-Ray diffraction (XRD) (1012) peak decreases considerably
with the use of SiN and TiN layers, indicating the reduction
in threading dislocation density. However, no direct
correlation is yet found between the decay times and the XRD
linewidths, suggesting that point defect and impurity
related nonradiative centers are the main parameters
affecting the lifetime.},
Doi = {10.4028/0-87849-425-1.1505},
Key = {Ozgur:2006bk}
}
@article{fds331993,
Author = {Avrutin, V and Ozgur, U and Izyumskaya, N and Chevtchenko, S and Leach,
J and Moore, JC and Baski, AA and Everitt, HO and Tsen, KT and Ruterana, P and Morkoc, H},
Title = {Morphology and optical properties of ZnO nanorods grown by
catalyst-assisted vapor transport on various
substrates},
Journal = {Materials Research Society Symposium Proceedings},
Volume = {963},
Pages = {153-158},
Year = {2006},
Month = {January},
ISBN = {9781604234152},
url = {http://dx.doi.org/10.1557/proc-0963-q15-20},
Abstract = {ZnO nanorods were grown by catalyst-assisted vapor phase
transport on Si(001), GaN(0001)/c-Al2O3, and bulk ZnO(0001)
substrates. Morphology studies showed that ZnO nanorods grew
mostly perpendicular to the GaN substrate surface, whereas a
more random directional distribution was found for nanorods
on Si. Optical properties of fabricated nanorods were
studied by steady-state photoluminescence and time-resolved
photoluminescence. Stimulated emission was observed from ZnO
nanorods on GaN substrates. Raman spectroscopy revealed
biaxial strain in the nanorod samples grown on Si.
Conductive atomic force microscopy was applied to study I-V
spectra of individual nanorods. © 2007 Materials Research
Society.},
Doi = {10.1557/proc-0963-q15-20},
Key = {fds331993}
}
@article{2006SPIE.6121...85X,
Author = {Xie, J and Fu, Y and {\"O}zg{\"u}r, {\"U}mit and Moon, Y. T. and Yun, F and Morko, H. and Everitt, Henry O and Sagar, A and Feenstra, R. M. and Inoki, C K and Kuan, T S and Zhou, L and Smith, D. J.},
Title = {Characterization of GaN epitaxial films grown on SiNx and
TiNx porous network templates},
Journal = {Gallium Nitride Materials and Devices. Edited by
Litton},
Volume = {6121},
Pages = {85--96},
Organization = {Virginia Commonwealth Univ. (USA)},
Institution = {Virginia Commonwealth Univ. (USA)},
Year = {2006},
Month = {March},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006SPIE.6121...85X&link_type=ABSTRACT},
Abstract = {We report on the structural, electrical, and optical
characterization of GaN epitaxial layers grown by
metalorganic chemical vapor deposition (MOCVD) on SiNx and
TiNx porous templates in order to reduce the density of
extended defects. Observations by transmission electron
microscopy (TEM) indicate an order of magnitude reduction in
the dislocation density in GaN layers grown on TiNx and SiNx
networks (down to ~108 cm-2) compared with the control GaN
layers. Both SiNx and TiNx porous network structures are
found to be effective in blocking the threading dislocation
from penetrating into the upper layer. Supporting these
findings are the results from X-Ray diffraction and low
temperature photoluminescence (PL) measurements. The
linewidth of the asymmetric X-Ray diffraction (XRD) (1012)
peak decreases considerably for the layers grown with the
use of SiNx and TiNx layers, which generally suggests the
reduction of edge and mixed threading dislocations. In
general, further improvement is observed with the addition
of a second SiNx layer. The room temperature decay times
obtained from biexponential fits to time-resolved
photoluminescence (TRPL) data are increased with the
inclusion of SiNx and TiNx layers. TRPL results suggest that
primarily point-defect and impurity-related nonradiative
centers are responsible for reducing the lifetime. The
carrier lifetime of 1.86 ns measured for a TiNx network
sample is slightly longer than that for a 200 $\mu$m-thick
high quality freestanding GaN. Results on samples grown by a
new technique called crack-assisted lateral overgrowth,
which combines in situ deposition of SiNx mask and
conventional lateral overgrowth, are also
reported.},
Doi = {10.1117/12.646858},
Key = {2006SPIE.6121...85X}
}
@article{fds314051,
Author = {Özgür, U and Gu, X and Chevtchenko, S and Spradlin, J and Cho, SJ and Morkoç, H and Pollak, FH and Everitt, HO and Nemeth, B and Nause,
JE},
Title = {Thermal conductivity of bulk ZnO after different thermal
treatments},
Journal = {Journal of Electronic Materials},
Volume = {35},
Number = {4},
Pages = {550-555},
Publisher = {Springer Nature},
Year = {2006},
Month = {April},
ISSN = {0361-5235},
url = {http://dx.doi.org/10.1007/s11664-006-0098-9},
Abstract = {Thermal conductivities (K) of melt-grown bulk ZnO samples
thermally treated under different conditions were measured
using scanning thermal microscopy. Samples annealed in air
at 1050°C for 3 h and treated with N-plasma at 750°C for 1
min. exhibited κ = 1.35 ± 0.08 W/cm-K and κ = 1.47 ±
0.08 W/cm-K, respectively. These are the highest values
reported for ZnO. Atomic force microscopy (AFM) and
conductive-AFM measurements revealed that surface carrier
concentration as well as surface morphology affected the
thermal conductivity.},
Doi = {10.1007/s11664-006-0098-9},
Key = {fds314051}
}
@article{fds314064,
Author = {Xie, J and Fu, Y and Özgür, U and Moon, YT and Yun, F and Morkoç, H and Everitt, HO and Sagar, A and Feenstra, RM and Inoki, CK and Kuan, TS and Zhou, L and Smith, DJ},
Title = {Characterization of GaN epitaxial films grown on SiN
x and TiN x porous network
templates},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6121},
Publisher = {SPIE},
Year = {2006},
Month = {May},
ISBN = {0819461636},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.646858},
Abstract = {We report on the structural, electrical, and optical
characterization of GaN epitaxial layers grown by
metalorganic chemical vapor deposition (MOCVD) on SiN x and
TiN x, porous templates in order to reduce the density of
extended defects. Observations by transmission electron
microscopy (TEM) indicate an order of magnitude reduction in
the dislocation density in GaN layers grown on TiN x and SiN
x networks (down to ∼10 8 cm -2) compared with the control
GaN layers. Both SiN x and TiN x porous network structures
are found to be effective in blocking the threading
dislocation from penetrating into the upper layer.
Supporting these findings are the results from X-Ray
diffraction and low temperature photoluminescence (PL)
measurements. The linewidth of the asymmetric X-Ray
diffraction (XRD) (1012) peak decreases considerably for the
layers grown with the use of SiN x and TiN x layers, which
generally suggests the reduction of edge and mixed threading
dislocations. In general, further improvement is observed
with the addition of a second SiN x layer. The room
temperature decay times obtained from biexponential fits to
time-resolved photoluminescence (TRPL) data are increased
with the inclusion of SiN x and TiN x layers. TRPL results
suggest that primarily point-defect and impurity-related
nonradiative centers are responsible for reducing the
lifetime. The carrier lifetime of 1.86 ns measured for a TiN
x network sample is slightly longer than that for a 200
μm-thick high quality freestanding GaN. Results on samples
grown by a new technique called crack-assisted lateral
overgrowth, which combines in situ deposition of SiN x mask
and conventional lateral overgrowth, are also
reported.},
Doi = {10.1117/12.646858},
Key = {fds314064}
}
@article{2006ApPhL..88v1906G,
Author = {Gollakota, P and Dhawan, A and Wellenius, P and Lunardi, LM and Muth,
JF and Saripalli, YN and Peng, HY and Everitt, HO},
Title = {Optical characterization of Eu-doped Β-Ga 2O
3 thin films},
Journal = {Applied Physics Letters},
Volume = {88},
Number = {22},
Pages = {221906-221906},
Publisher = {AIP Publishing},
Organization = {Department of Electrical and Computer Engineering, North
Carolina State University, Raleigh, North Carolina
27606},
Institution = {Department of Electrical and Computer Engineering, North
Carolina State University, Raleigh, North Carolina
27606},
Year = {2006},
Month = {May},
ISSN = {0003-6951},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006ApPhL..88v1906G&link_type=ABSTRACT},
Abstract = {Europium-doped Β- Ga2 O3 thin films were grown on
double-side polished c -axis (0001) sapphire substrates by
pulsed laser deposition at 850 °C. Transmission
measurements of the films revealed a sharp band edge with a
band gap at 5.0 eV. The films exhibited intense red emission
at 611 nm (2.03 eV) due to the transitions from D05 to F27
levels in europium, with intensities that increased with the
concentration of europium. Time-resolved photoluminescence
measurements revealed a temperature-insensitive lifetime of
1.4 ms, which is much longer than the lifetimes of europium
luminescence observed in GaN hosts. © 2006 American
Institute of Physics.},
Doi = {10.1063/1.2208368},
Key = {2006ApPhL..88v1906G}
}
@article{Foreman06,
Author = {Foreman, JV and Li, J and Peng, H and Choi, S and Everitt, HO and Liu,
J},
Title = {Time-resolved investigation of bright visible wavelength
luminescence from sulfur-doped ZnO nanowires and
micropowders.},
Journal = {Nano Letters},
Volume = {6},
Number = {6},
Pages = {1126-1130},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2006},
Month = {June},
ISSN = {1530-6984},
url = {http://pubs.acs.org/doi/abs/10.1021/nl060204z},
Abstract = {Sulfur-doped zinc oxide (ZnO) nanowires grown on gold-coated
silicon substrates inside a horizontal tube furnace exhibit
remarkably strong visible wavelength emission with a quantum
efficiency of 30%, an integrated intensity 1600 times
stronger than band edge ultraviolet emission, and a spectral
distribution that closely matches the dark-adapted human eye
response. By comparatively studying sulfur-doped and undoped
ZnO micropowders, we clarify how sulfur doping and
nanostructuring affect the visible luminescence and the
underlying energy transfer mechanisms.},
Language = {English},
Doi = {10.1021/nl060204z},
Key = {Foreman06}
}
@article{Choi:2006iy,
Author = {Choi, S and Kim, TH and Brown, A and Everitt, HO and Losurdo, M and Bruno,
G and Moto, A},
Title = {Kinetics of gallium adsorption and desorption on (0001)
gallium nitride surfaces},
Journal = {Applied Physics Letters},
Volume = {89},
Number = {18},
Pages = {181915-181915},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2006},
Month = {November},
ISSN = {0003-6951},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000089000018181915000001&idtype=cvips&gifs=yes},
Abstract = {In situ spectroscopic ellipsometry kinetic characterization
is used to monitor the behavior of Ga atoms during and after
Ga flux impingement upon a (0001) GaN surface at various
temperatures in the range of 680-750 °C. The observed
saturation of the pseudodielectric function verifies the
existence of a critical thickness for the Ga wetting layer,
while the observed desorption delay after the Ga flux is
terminated indicates the presence of two Ga phases, one
acting as a Ga reservoir to compensate the desorption of the
wetting layer until the other phase is depleted. © 2006
American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.2372744},
Key = {Choi:2006iy}
}
@article{Porter:2006p1270,
Author = {Porter, HL and Muth, JF and Narayan, J and Foreman, JV and Everitt,
HO},
Title = {Photoluminescence study of ZnO films codoped with nitrogen
and tellurium},
Journal = {Journal of Applied Physics},
Volume = {100},
Number = {12},
Pages = {123102-123102},
Publisher = {AIP Publishing},
Organization = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27695 USA},
Institution = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27695 USA},
Year = {2006},
Month = {December},
ISSN = {0021-8979},
url = {http://link.aip.org/link/?JAPIAU/100/123102/1},
Abstract = {Epitaxial ZnO films codoped with tellurium and nitrogen were
grown by pulsed laser deposition on c -axis oriented
sapphire substrates. The codoping strategy allowed the
resistivity of the films to be controlled over several
orders of magnitude and may prove useful in the development
of ZnO based light emitters. Photoluminescence studies of
tellurium-doped, nitrogen-doped, tellurium and nitrogen
codoped, and undoped ZnO films were conducted. Strong room
temperature photoluminescence and stimulated emission were
observed in the undoped and Te-doped films, but not in
codoped films. Time-resolved photoluminescence measurements
indicated that carrier lifetime was significantly reduced in
doped ZnO as compared to undoped ZnO. © 2006 American
Institute of Physics.},
Doi = {10.1063/1.2372312},
Key = {Porter:2006p1270}
}
@article{Ozgur:2006p1275,
Author = {Özgür, U and Ni, X and Fu, Y and Morko̧, H and Everitt,
HO},
Title = {Near-field scanning optical microscopy and time-resolved
optical characterization of epitaxial lateral overgrown
c-plane and a-plane GaN},
Journal = {Applied Physics Letters},
Volume = {89},
Number = {26},
Pages = {262117-262117},
Publisher = {AIP Publishing},
Organization = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Year = {2006},
Month = {December},
ISSN = {0003-6951},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000089000026262117000001&idtype=cvips&gifs=yes},
Abstract = {Epitaxial lateral overgrowth (ELO) was employed for both c
-plane and a -plane GaN layers on sapphire, and a more
pronounced optical improvement was observed for the a -plane
GaN as evidenced by the significantly increased band edge
photoluminescence (PL). Room temperature near-field scanning
optical microscopy studies explicitly showed enhanced
optical quality in the wing regions of the overgrown GaN due
to reduced density of dislocations, and for the a -plane ELO
GaN sample the wings and the windows were clearly
discernible from PL mapping. Time-resolved PL measurements
revealed biexponential decays with time constants that were
significantly enhanced for the a -plane ELO GaN (τ1 =0.08
ns, τ2 =0.25 ns) when compared to the non-ELO control
sample but were still much shorter than those for the c
-plane ELO GaN (τ1 =0.26 ns, τ2 =0.90 ns). © 2006
American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.2424677},
Key = {Ozgur:2006p1275}
}
@article{2007ApPhL..90j3119W,
Author = {Wu, PC and Kim, T-H and Brown, AS and Losurdo, M and Bruno, G and Everitt,
HO},
Title = {Real-time plasmon resonance tuning of liquid Ga
nanoparticles by in situ spectroscopic ellipsometry},
Journal = {Applied Physics Letters},
Volume = {90},
Number = {10},
Pages = {103119},
Publisher = {AIP Publishing},
Organization = {Department of Electrical and Computer Engineering, Duke
University, Durham, North Carolina 27708},
Institution = {Department of Electrical and Computer Engineering, Duke
University, Durham, North Carolina 27708},
Year = {2007},
url = {http://dx.doi.org/10.1063/1.2712508},
Abstract = {Liquid Ga nanoparticles have been deposited on sapphire
substrates at room temperature. The optical evolution of Ga
nanoparticle surface plasmon resonance during deposition has
been characterized by in situ real-time spectroscopic
ellipsometry to control and tune the plasmon resonance
photon energy. The existence of both longitudinal and
transverse modes for spheroidal Ga nanoparticles supported
on a sapphire substrate is demonstrated and the dependence
of the longitudinal and transverse plasmon energies on
particle size is discussed. Stability of the Ga surface
plasmon resonance to air exposure and high temperature is
also demonstrated. © 2007 American Institute of
Physics.},
Doi = {10.1063/1.2712508},
Key = {2007ApPhL..90j3119W}
}
@article{Foreman:2007p1262,
Author = {Foreman, J and Everitt, H and Yang, J and Liu, J},
Title = {Influence of temperature and photoexcitation density on the
quantum efficiency of defect emission in ZnO
powders},
Journal = {Applied Physics Letter},
Volume = {91},
Number = {91},
Pages = {011902-011902},
Publisher = {AIP Publishing},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2007},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000091000001011902000001&idtype=cvips&gifs=yes},
Abstract = {The effect of laser excitation power density on the
efficiency of intrinsic defect emission in ZnO powders was
characterized by varying the laser irradiance over three
orders of magnitude and monitoring changes in the samples'
photoluminescence. The external quantum efficiency of the
visible wavelength, broadband defect photoluminescence was
found to depend not only on laser irradiance but also on
temperature and prior annealing conditions. This material
system is potentially useful as an ultraviolet-photoexcited,
white light phosphor under low-power excitation (<0.2 W cm2)
at room temperature and below. © 2007 American Institute of
Physics.},
Language = {English},
Doi = {10.1063/1.2753540},
Key = {Foreman:2007p1262}
}
@article{Peng:2007p1265,
Author = {Peng, Hongying and Lee, Chang-Won and Everitt, Henry O and Munasinghe, Chanaka and Lee, D S and Steckl, Andrew
J},
Title = {Spectroscopic and energy transfer studies of Eu3+ centers in
GaN},
Journal = {Journal of Applied Physics},
Volume = {102},
Number = {7},
Pages = {--},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2007},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JAPIAU000102000007073520000001&idtype=cvips&gifs=yes},
Abstract = {Photoluminescence (PL), photoluminescence excitation (PLE),
and time-resolved PL spectroscopies have been carried out at
room temperature and 86 K on transitions from D-5(2),
D-5(1), and D-5(0) excited states to numerous F-7(J) ground
states of Eu-doped GaN films grown by conventional
solid-source molecular beam epitaxy (MBE) and interrupted
growth epitaxy MBE. Within the visible spectral range of
1.8-2.7 eV, 42 spectral features were observed and
assignments were attempted for each transition. PL and PLE
indicate that four Eu3+ centers exist in the GaN lattice
whose relative concentration can be controlled by the
duration of growth interruption. The energy levels for these
four sites are self-consistently obtained, and time-resolved
photoluminescence measurements reveal details about the
radiative and nonradiative relaxations of excitation among
these levels. The data indicate a near-resonant cross
relaxation among these sites. The D-5(2) and D-5(1) states
are observed to decay nonradiatively by filling the D-5(0)
state with characteristic times of 2.4 and 2.8 mu s,
respectively. The D-5(0) state is found to relax in a manner
that depends slightly on the final state and dopant site.
(C) 2007 American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.2783893},
Key = {Peng:2007p1265}
}
@article{Ni:2007p1267,
Author = {Ni, X and Oezguer, Ue and Morko{\c c}, H and Liliental-Weber, Z and Everitt, H O},
Title = {Epitaxial lateral overgrowth of a-plane GaN by metalorganic
chemical vapor deposition},
Journal = {Journal of Applied Physics},
Volume = {102},
Number = {5},
Pages = {--},
Organization = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Institution = {Virginia Commonwealth Univ, Dept Elect Engn, Richmond, VA
23284 USA},
Year = {2007},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JAPIAU000102000005053506000001&idtype=cvips&gifs=yes},
Abstract = {We report on epitaxial lateral overgrowth (ELO) of
(<11(2)over bar0>) a-plane GaN by metalorganic chemical
vapor deposition. Different growth rates of Ga- and N-polar
wings together with wing tilt create a major obstacle for
achieving a smooth, fully coalesced surface in ELO a-plane
GaN. To address this issue a two-step growth method was
employed to provide a large aspect ratio of height to width
in the first growth step followed by enhanced lateral growth
in the second by controlling the growth temperature. By this
method, the average ratio of Ga- to N-polar wing growth rate
has been reduced from 4-6 to 1.5-2, which consequently
reduced the wing-tilt induced height difference between the
two approaching wings at the coalescence front, thereby
making their coalescence much easier. Transmission electron
microscopy showed that the threading dislocation density in
the wing regions was 1.0x10(8) cm(-2), more than two orders
of magnitude lower than that in the window regions
(4.2x10(10) cm(-2)). However, a relatively high density of
basal stacking faults of 1.2x10(4) cm(-1) was still present
in the wing regions as compared to c -plane GaN, where they
are rarely observed away from the substrate. Atomic force
microscopy (AFM) measurements showed two orders of magnitude
higher density of surface pits in the window than in the
wing regions, which were considered to be terminated by
dislocations (partial ones related to stacking faults and
full ones) on the surface. The existence of basal stacking
faults was also revealed by AFM measurements on the a-plane
ELO sample after wet chemical etching in hot H3PO4/H2SO4
(1:1). The extensions of Ga-polar wings near the meeting
fronts were almost free of stacking faults. The improvement
of crystalline quality in the overgrown layer by ELO was
also verified by near field scanning optical microscopy and
time-resolved photoluminescence measurements; the former
showing strongly enhanced luminescence from the wing
regions, and the latter indicating longer decay times (0.25
ns) compared to a standard a-plane GaN template (40 ps). (C)
2007 American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.2773692},
Key = {Ni:2007p1267}
}
@article{StiffRoberts:2007p1279,
Author = {Stiff-Roberts, Adrienne D and Zhang, Wanming and Xu, Jian and Peng, Hongying and Everitt, Henry O},
Title = {Spin-cast deposition of CdSe-CdS core-shell colloidal
quantum dots on doped GaAs substrates: Structural and
optical characterization},
Journal = {IEEE Transactions On Nanotechnology},
Volume = {6},
Number = {4},
Pages = {413--420},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2007},
Month = {January},
url = {http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=4268347},
Abstract = {The detailed study of the effects of spin recipe and GaAs
substrate doping (i.e., semi-insulating, n-type, or p-type)
on the structural and optical properties of spin-cast
CdSe-CdS core-shell CQDs provides insight into the surface
adsorption and charge transfer mechanisms that will
influence any potential optoelectronic device. The
hypotheses of this study are: i) it is possible to establish
spin-casting recipes that yield a thin film of CQDs with
large surface density and uniform size, and ii) it is
possible to control the optical response of CQDs by varying
the GaAs substrate doping to influence charge transfer
processes. As a result of these measurements, we have been
able to demonstrate " strong dependence of spin-cast CQD
structural properties on the doping type of the GaAs
substrate, as well as evidence from measured optical
properties to support the idea that hot carriers
photoexcited in the GaAs substrate are transferred either to
the CQD surface states through organic surface ligands or
directly to confined states within the CQD.},
Language = {English},
Doi = {10.1109/TNANO.2007.896845},
Key = {StiffRoberts:2007p1279}
}
@article{StiffRoberts:2007ki,
Author = {Stiff-Roberts, Adrienne D and Zhang, Wanming and Xu, Jian and Peng, Hongying and Everitt, Henry O},
Title = {Spin-cast deposition of CdSe-CdS core-shell colloidal
quantum dots on doped GaAs substrates: Structural and
optical characterization},
Journal = {Ieee Transactions On Nanotechnology},
Volume = {6},
Number = {4},
Pages = {413--420},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2007},
Month = {January},
url = {http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=4268347},
Abstract = {The detailed study of the effects of spin recipe and GaAs
substrate doping (i.e., semi-insulating, n-type, or p-type)
on the structural and optical properties of spin-cast
CdSe-CdS core-shell CQDs provides insight into the surface
adsorption and charge transfer mechanisms that will
influence any potential optoelectronic device. The
hypotheses of this study are: i) it is possible to establish
spin-casting recipes that yield a thin film of CQDs with
large surface density and uniform size, and ii) it is
possible to control the optical response of CQDs by varying
the GaAs substrate doping to influence charge transfer
processes. As a result of these measurements, we have been
able to demonstrate " strong dependence of spin-cast CQD
structural properties on the doping type of the GaAs
substrate, as well as evidence from measured optical
properties to support the idea that hot carriers
photoexcited in the GaAs substrate are transferred either to
the CQD surface states through organic surface ligands or
directly to confined states within the CQD.},
Language = {English},
Doi = {10.1109/TNANO.2007.896845},
Key = {StiffRoberts:2007ki}
}
@inproceedings{Ni:2007ge,
Author = {Ni, X and {\"O}zg{\"u}r, {\"U}mit and Morko{\c c}, H and Baski, A A and Liliental-Weber, Z and Everitt, Henry
O},
Title = {Two-step epitaxial lateral overgrowth of a-plane GaN by
MOCVD},
Pages = {647303--647303--7},
Booktitle = {Gallium Nitride Materials and Devices II},
Publisher = {SPIE},
Year = {2007},
Month = {February},
url = {http://link.aip.org/link/PSISDG/v6473/i1/p647303/s1&Agg=doi},
Abstract = {We report on growth and characterization of epitaxial
lateral overgrown (ELO) (1120) a-plane GaN by metalorganic
chemical vapor deposition (MOCVD). The ELO samples were
grown using a SiO2 striped mask pattern consisting of 4
$\mu$m wide open windows and 10 $\mu$m or 20 $\mu$m wide
SiO2 stripes. Different growth rates in Ga- and N-wings
along with the wing tilt create a major obstacle for
achieving a fully coalesced flat surface in ELO-GaN. To
address this problem we have employed a two-step growth
method that is able to provide a high height to width aspect
ratio in the first growth step followed by enhanced lateral
growth in the second step by controlling the growth
temperature. Depending on the growth conditions, lateral
growth rate of the wings with Ga-polarity were from 2 to 5
times larger than that of the N- polarity wings. We
investigated the effects of growth parameters on wing tilt,
which was observed to be ~ 0.25$\,^{\circ}$ from the Kikuchi
lines using large angle convergent beam electron diffraction
(LACBED) and accompanied by some twist (0.09$\,^{\circ}$)
between the two opposite wings. Transmission electron
microscopy (TEM) results showed that the threading
dislocation density in the resulting fully coalesced
overgrown GaN was reduced from 4.2×1010 cm-2 in the window
area to 1.0×108 cm-2 in the wing area, and that the wing
areas contained relatively high density of basal stacking
faults, 1.2×104 cm-1. The recombination of
carriers/excitons localized at stacking faults was evident
in far-field near bandedge photoluminescence (PL) measured
at 10 K. Moreover, atomic force microscopy (AFM)
measurements revealed two orders of magnitude higher density
of surface pits in window than in wing regions, which could
be decorating dislocation termination on surface.
Time-resolved PL measurements for the a-plane ELO-GaN
samples revealed biexponential decays. The recombination
times were significantly increased ($\tau$1=80 ps and
$\tau$2=250 ps) compared to the standard a-plane epitaxial
layers (<45 ps), and ratio of the slow decaying component
magnitude to the fast decaying one was more than 1.5,
showing considerable reduction of nonradiative centers by
lateral overgrowth. In addition, room temperature near-field
optical microscopy studies revealed the improved optical
quality in the wing regions of the overgrown GaN. As
revealed from far-field PL, the band edge luminescence at
room temperature was more than two orders of magnitude
weaker than the yellow luminescence. Therefore, the overall
spectrally integrated near field PL was collected, and its
intensity was noticeably stronger in the wing areas with
both Ga and N polarity. The much weaker emission at the
windows and meeting fronts of the two opposite wings were
consistent with the observations of high density of
dislocations in the window regions and new defects
originating at the meeting boundaries from
TEM.},
Language = {English},
Doi = {10.1117/12.706826},
Key = {Ni:2007ge}
}
@inproceedings{Avrutin:2007hk,
Author = {Avrutin, V and {\"O}zg{\"u}r, {\"U}mit and Izyumskaya, N and Chevtchenko, S and Leach, J and Moore, J C and Baski, A A and Litton, C and Everitt, Henry O and Tsen, K T and Abouzaid, M and Ruterana, P and Morko{\c c},
H},
Title = {Carrier relaxation and stimulated emission in ZnO nanorods
grown by catalyst-assisted vapor transport on various
substrates},
Pages = {64741M--64741M--7},
Booktitle = {Zinc Oxide Materials and Devices II},
Publisher = {SPIE},
Year = {2007},
Month = {February},
url = {http://link.aip.org/link/PSISDG/v6474/i1/p64741M/s1&Agg=doi},
Abstract = {ZnO nanorods were grown by catalyst-assisted vapor phase
transport on Si(001), GaN(0001)/c-Al2O3, and bulk ZnO(0001)
substrates. Morphology studies as well as X-ray diffraction
and transmission electron microscopy showed that ZnO
nanorods grew mostly perpendicular to the GaN(0001) and
ZnO(0001) substrate surface, whereas a more random
directional distribution was found for nanorods on Si(001).
Comprehensive optical properties of nanorods were studied by
steady-state photoluminescence and time-resolved
photoluminescence. Stimulated emission was observed from ZnO
nanorods on GaN(0001)/c-Al2O3 substrates, most likely due to
their vertical orientation. Near- field scanning optical
microscopy was applied to investigate luminescent properties
of individual rods. Raman spectroscopy revealed biaxial
compressive strain in the nanorod samples grown on Si(001).
The strain magnitude was reducing with increasing length of
the nanorods. Conductive atomic force microscopy showed that
nanorods are electrically isolated from each other. I-V
spectra of individual nanorods were measured.},
Language = {English},
Doi = {10.1117/12.708835},
Key = {Avrutin:2007hk}
}
@inproceedings{Xie:2007dy,
Author = {Xie, J and {\"O}zg{\"u}r, {\"U}mit and Fu, Y and Ni, X and Morko{\c c}, H and Inoki, C K and Kuan, T S and Foreman,
John V and Everitt, Henry O},
Title = {Low dislocation density GaN grown by MOCVD with SiNx
nano-network},
Pages = {647304--647304--8},
Booktitle = {Gallium Nitride Materials and Devices II},
Publisher = {SPIE},
Year = {2007},
Month = {February},
url = {http://link.aip.org/link/PSISDG/v6473/i1/p647304/s1&Agg=doi},
Abstract = {GaN epitaxial layers grown on SiC and sapphire suffer from
high density of line and point defects. To address this
problem, new growth methods using in situ or ex situ
nano-network masks as dislocation filters have been
introduced recently. In this work, we report on metalorganic
chemical vapor deposition (MOCVD) of GaN layers on 2-inch
sapphire substrates using in situ SiNx nano-networks
intended for defect reduction. SiNx interlayers with
different deposition times were employed after ~2 $\mu$m GaN
grown on sapphire, which was followed by ~3.5 $\mu$m GaN
overgrowth. With increasing SiNx coverage, full width at
hall maximum (FWHM) values of (0002) and (10 1 2) X-Ray
diffraction (XRD) peaks monotonously decrease from 252 arc
sec to 217 arc sec and from 405 ar csec to 211 arc sec,
respectively for a 5.5 $\mu$m thick film. Similarly,
transmission electron microscopy (TEM) revealed that screw
and edge type dislocation densities as low as 4.4×107 cm-2
and 1.7×107 cm-2 were achieved. The use of SiNx nanonetwork
also increases the radiative recombination lifetimes
measured by time-resolved photoluminescence to 2.5 ns from
less than 0.5 ns in control GaN. We have also fabricated
Ni/Au Schottky diodes on the overgrown GaN layers and the
diode performance was found to depend critically on SiNx
coverage, consistent with TEM, XRD and TRPL results. A
1.13eV barrier height was achieved when SiNx layer was used
compared to 0.78 eV without any SiNx nanonetwork.
Furthermore, the breakdown voltage was improved from 76 V to
250 V with SiNx nanonetwork.},
Language = {English},
Doi = {10.1117/12.706936},
Key = {Xie:2007dy}
}
@article{2007ApPhL..90d1107X,
Author = {Xie, J and Özgür, U and Fu, Y and Ni, X and Morko̧, H and Inoki, CK and Kuan, TS and Foreman, JV and Everitt, HO},
Title = {Low dislocation densities and long carrier lifetimes in GaN
thin films grown on a Si Nx nanonetwork},
Journal = {Applied Physics Letters},
Volume = {90},
Number = {4},
Pages = {041107-041107},
Publisher = {AIP Publishing},
Organization = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284},
Institution = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284},
Year = {2007},
Month = {February},
ISSN = {0003-6951},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000243789600007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Significant improvement of structural and optical qualities
of GaN thin films on sapphire substrates was achieved by
metal organic chemical vapor deposition with in situ Si Nx
nanonetwork. Transmission electron microscope (TEM) studies
revealed that screw- and edge-type dislocations were reduced
to 4.4× 107 and 1.7× 107 cm-2, respectively, for a
∼5.5-μm -thick layer. Furthermore, room temperature
carrier lifetimes of 2.22 and 2.49 ns were measured by
time-resolved photoluminescence (TRPL) for samples
containing single and double Si Nx network layers,
respectively, representing a significant improvement over
the previous studies. The consistent trends among the TEM,
x-ray diffraction, and TRPL measurements suggest that in
situ Si Nx network reduces line defects effectively as well
as the point-defect-related nonradiative centers. © 2007
American Institute of Physics.},
Doi = {10.1063/1.2433754},
Key = {2007ApPhL..90d1107X}
}
@article{fds314091,
Author = {Avrutin, V and Özgür, U and Izyumskaya, N and Chevtchenko, S and Leach, J and Moore, JC and Baski, AA and Litton, C and Everitt, HO and Tsen, KT and Abouzaid, M and Ruterana, P and Morkoç,
H},
Title = {Carrier relaxation and stimulated emission in ZnO nanorods
grown by catalyst-assisted vapor transport on various
substrates},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6474},
Publisher = {SPIE},
Year = {2007},
Month = {May},
ISBN = {0819465879},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.708835},
Abstract = {ZnO nanorods were grown by catalyst-assisted vapor phase
transport on Si(001), GaN(0001)/c-Al2O3, and bulk ZnO(0001)
substrates. Morphology studies as well as X-ray diffraction
and transmission electron microscopy showed that ZnO
nanorods grew mostly perpendicular to the GaN(0001) and
ZnO(0001) substrate surface, whereas a more random
directional distribution was found for nanorods on Si(001).
Comprehensive optical properties of nanorods were studied by
steady-state photoluminescence and time-resolved
photoluminescence. Stimulated emission was observed from ZnO
nanorods on GaN(0001)/c-Al2O3 substrates, most likely due to
their vertical orientation. Near-field scanning optical
microscopy was applied to investigate luminescent properties
of individual rods. Raman spectroscopy revealed biaxial
compressive strain in the nanorod samples grown on Si(001).
The strain magnitude was reducing with increasing length of
the nanorods. Conductive atomic force microscopy showed that
nanorods are electrically isolated from each other. I-V
spectra of individual nanorods were measured.},
Doi = {10.1117/12.708835},
Key = {fds314091}
}
@article{fds318425,
Author = {Xie, J and Özgür, U and Fu, Y and Ni, X and Morkoç, H and Inoki, CK and Kuan, TS and Foreman, JV and Everitt, HO},
Title = {Low dislocation density GaN grown by MOCVD with
SiNx nano-network},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6473},
Publisher = {SPIE},
Year = {2007},
Month = {May},
ISBN = {0819465860},
url = {http://dx.doi.org/10.1117/12.706936},
Abstract = {GaN epitaxial layers grown on SiC and sapphire suffer from
high density of line and point defects. To address this
problem, new growth methods using in situ or ex situ
nano-network masks as dislocation filters have been
introduced recently. In this work, we report on metalorganic
chemical vapor deposition (MOCVD) of GaN layers on 2-inch
sapphire substrates using in situ SiN x nano-networks
intended for defect reduction. SiNx interlayers with
different deposition times were employed after ∼2 μm GaN
grown on sapphire, which was followed by ∼3.5 μm GaN
overgrowth. With increasing SiNx coverage, full width at
hall maximum (FWHM) values of (0002) and (101̄2) X-Ray
diffraction (XRD) peaks monotonously decrease from 252 arc
sec to 217 arc sec and from 405 ar csec to 211 arc sec,
respectively for a 5.5 μm thick film. Similarly,
transmission electron microscopy (TEM) revealed that screw
and edge type dislocation densities as low as 4.4×107 cm-2
and 1.7×107 cm -2 were achieved. The use of SiNx
nanonetwork also increases the radiative recombination
lifetimes measured by time-resolved photoluminescence to 2.5
ns from less than 0.5 ns in control GaN. We have also
fabricated Ni/Au Schottky diodes on the overgrown GaN layers
and the diode performance was found to depend critically on
SiNx coverage, consistent with TEM, XRD and TRPL results. A
1.13eV barrier height was achieved when SiNx layer was used
compared to 0.78 eV without any SiN x nanonetwork.
Furthermore, the breakdown voltage was improved from 76 V to
250 V with SiNx nanonetwork.},
Doi = {10.1117/12.706936},
Key = {fds318425}
}
@article{fds318426,
Author = {Ni, X and Özgür, U and Morkoç, H and Baski, AA and Liliental-Weber,
Z and Everitt, HO},
Title = {Two-step epitaxial lateral overgrowth of a-plane GaN by
MOCVD},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6473},
Pages = {47303-47303},
Publisher = {SPIE},
Year = {2007},
Month = {May},
ISBN = {0819465860},
url = {http://dx.doi.org/10.1117/12.706826},
Abstract = {We report on growth and characterization of epitaxial
lateral overgrown (ELO) (112̄0) a-plane GaN by metalorganic
chemical vapor deposition (MOCVD). The ELO samples were
grown using a SiO2 striped mask pattern consisting of 4 μm
wide open windows and 10 μm or 20 μm wide SiO 2 stripes.
Different growth rates in Ga- and N-wings along with the
wing tilt create a major obstacle for achieving a fully
coalesced flat surface in ELO-GaN. To address this problem
we have employed a two-step growth method that is able to
provide a high height to width aspect ratio in the first
growth step followed by enhanced lateral growth in the
second step by controlling the growth temperature. Depending
on the growth conditions, lateral growth rate of the wings
with Ga-polarity were from 2 to 5 times larger than that of
the N-polarity wings. We investigated the effects of growth
parameters on wing tilt, which was observed to be ∼ 0.25°
from the Kikuchi lines using large angle convergent beam
electron diffraction (LACBED) and accompanied by some twist
(0.09°) between the two opposite wings. Transmission
electron microscopy (TEM) results showed that the threading
dislocation density in the resulting fully coalesced
overgrown GaN was reduced from 4.2×10 10 cm-2 in the window
area to 1.0×108 cm-2 in the wing area, and that the wing
areas contained relatively high density of basal stacking
faults, 1.2×104 cm-1. The recombination of
carriers/excitons localized at stacking faults was evident
in far-field near bandedge photoluminescence (PL) measured
at 10 K. Moreover, atomic force microscopy (AFM)
measurements revealed two orders of magnitude higher density
of surface pits in window than in wing regions, which could
be decorating dislocation termination on surface.
Time-resolved PL measurements for the a-plane ELO-GaN
samples revealed biexponential decays. The recombination
times were significantly increased (τ1=80 ps and τ2=250
ps) compared to the standard a-plane epitaxial layers (<45
ps), and ratio of the slow decaying component magnitude to
the fast decaying one was more than 1.5, showing
considerable reduction of nonradiative centers by lateral
overgrowth. In addition, room temperature near-field optical
microscopy studies revealed the improved optical quality in
the wing regions of the overgrown GaN. As revealed from
far-field PL, the band edge luminescence at room temperature
was more than two orders of magnitude weaker than the yellow
luminescence. Therefore, the overall spectrally integrated
near field PL was collected, and its intensity was
noticeably stronger in the wing areas with both Ga and N
polarity. The much weaker emission at the windows and
meeting fronts of the two opposite wings were consistent
with the observations of high density of dislocations in the
window regions and new defects originating at the meeting
boundaries from TEM.},
Doi = {10.1117/12.706826},
Key = {fds318426}
}
@article{Choi:2007p1278,
Author = {Choi, S and Kim, TH and Everitt, HO and Brown, A and Losurdo, M and Bruno,
G and Moto, A},
Title = {Kinetics of gallium adlayer adsorption/desorption on polar
and nonpolar GaN surfaces},
Journal = {Journal of Vacuum Science & Technology. B, Microelectronics
and Nanometer Structures : Processing, Measurement, and
Phenomena : an Official Journal of the American Vacuum
Society},
Volume = {25},
Number = {3},
Pages = {969-973},
Publisher = {American Vacuum Society},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2007},
Month = {June},
ISSN = {1071-1023},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JVTBD9000025000003000969000001&idtype=cvips&gifs=yes},
Abstract = {Spectroscopic ellipsometry installed on a GEN-II plasma
assisted molecular beam epitaxy machine has been shown to be
an effective in situ real time tool for monitoring the
kinetics of gallium adlayer adsorption/desorption on the GaN
surface. In this work, the authors present data on the study
of Ga adsorption/desorption on polar c -plane GaN (0001) and
nonpolar m -plane GaN (1-100) surfaces for Ga beam
equivalent pressures in the range of 8.96× 10-8 -1.86×
10-7 Torr, Ga pulses in the range of 5-360 s, and for
substrate temperatures between 650 and 750 °C. © 2007
American Vacuum Society.},
Language = {English},
Doi = {10.1116/1.2720856},
Key = {Choi:2007p1278}
}
@article{fds314145,
Author = {Stiff Roberts and AD and Zhang, W and Xu, J and Peng, H and Everitt,
HO},
Title = {Spin-cast Deposition of CdSe-CdS Core-shell Colloidal
Quantum Dots on Doped GaAs Substrates: Structural and
Optical Characterization},
Journal = {Ieee Transactions on Nanotechnology},
Volume = {6},
Number = {4},
Pages = {413-420},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2007},
Month = {July},
url = {http://dx.doi.org/10.1109/TNANO.2007.896845},
Abstract = {The detailed study of the effects of spin recipe and GaAs
substrate doping (i.e., semi-insulating, ç-type, or p-type)
on the structural and optical properties of spin-cast
CdSe-CdS core-shell CQDs provides insight into the surface
adsorption and charge transfer mechanisms that will
influence any potential optoelectronic device. The
hypotheses of this study are: i) it is possible to establish
spin-casting recipes that yield a thin film of CQDs with
large surface density and uniform size, and ii) it is
possible to control the optical response of CQDs by varying
the GaAs substrate doping to influence charge transfer
processes. As a result of these measurements, we have been
able to demonstrate a strong dependence of spin-cast CQD
structural properties on the doping type of the GaAs
substrate, as well as evidence from measured optical
properties to support the idea that hot carriers
photoexcited in the GaAs substrate are transferred either to
the CQD surface states through organic surface ligands or
directly to confined states within the CQD. © 2007
IEEE.},
Doi = {10.1109/TNANO.2007.896845},
Key = {fds314145}
}
@article{2007JAP...102e3506N,
Author = {Ni, X and Özgür, U and Morko̧, H and Liliental-Weber, Z and Everitt,
HO},
Title = {Epitaxial lateral overgrowth of a -plane GaN by metalorganic
chemical vapor deposition},
Journal = {Journal of Applied Physics},
Volume = {102},
Number = {5},
Pages = {053506-053506},
Publisher = {AIP Publishing},
Organization = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284, USA},
Institution = {Department of Electrical Engineering, Virginia Commonwealth
University, Richmond, Virginia 23284, USA},
Year = {2007},
Month = {September},
ISSN = {0021-8979},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007JAP...102e3506N&link_type=ABSTRACT},
Abstract = {We report on epitaxial lateral overgrowth (ELO) of (11 2- 0)
a -plane GaN by metalorganic chemical vapor deposition.
Different growth rates of Ga- and N-polar wings together
with wing tilt create a major obstacle for achieving a
smooth, fully coalesced surface in ELO a -plane GaN. To
address this issue a two-step growth method was employed to
provide a large aspect ratio of height to width in the first
growth step followed by enhanced lateral growth in the
second by controlling the growth temperature. By this
method, the average ratio of Ga- to N-polar wing growth rate
has been reduced from 4-6 to 1.5-2, which consequently
reduced the wing-tilt induced height difference between the
two approaching wings at the coalescence front, thereby
making their coalescence much easier. Transmission electron
microscopy showed that the threading dislocation density in
the wing regions was 1.0× 108 cm-2, more than two orders of
magnitude lower than that in the window regions (4.2× 1010
cm-2). However, a relatively high density of basal stacking
faults of 1.2× 104 cm-1 was still present in the wing
regions as compared to c -plane GaN, where they are rarely
observed away from the substrate. Atomic force microscopy
(AFM) measurements showed two orders of magnitude higher
density of surface pits in the window than in the wing
regions, which were considered to be terminated by
dislocations (partial ones related to stacking faults and
full ones) on the surface. The existence of basal stacking
faults was also revealed by AFM measurements on the a -plane
ELO sample after wet chemical etching in hot H3 PO4 H2 SO4
(1:1). The extensions of Ga-polar wings near the meeting
fronts were almost free of stacking faults. The improvement
of crystalline quality in the overgrown layer by ELO was
also verified by near field scanning optical microscopy and
time-resolved photoluminescence measurements; the former
showing strongly enhanced luminescence from the wing
regions, and the latter indicating longer decay times (0.25
ns) compared to a standard a -plane GaN template (40 ps). ©
2007 American Institute of Physics.},
Doi = {10.1063/1.2773692},
Key = {2007JAP...102e3506N}
}
@article{Lucia:2007p735,
Author = {de Lucia, Frank C and Petkie, Douglas T and Everitt, Henry
O},
Title = {A double resonance approach to submillimeter/terahertz
remote sensing at atmospheric pressure},
Journal = {arXiv},
Year = {2007},
Month = {October},
url = {http://arxiv.org/abs/0710.5887v1},
Abstract = {The remote sensing of gases in complex mixtures at
atmospheric pressure is a challenging problem and much
attention has been paid to it. The most fundamental
difference between this application and highly successful
astrophysical and upper atmospheric remote sensing is the
line width associated with atmospheric pressure broadening,
~ 5 GHz in all spectral regions. In this paper, we discuss
quantitatively a new approach that would use a short pulse
infrared laser to modulate the submillimeter/terahertz
(SMM/THz) spectral absorptions on the time scale of
atmospheric relaxation. We show that such a scheme has three
important attributes: (1) The time resolved pump makes it
possible and efficient to separate signal from atmospheric
and system clutter, thereby gaining as much as a factor of
10^6 in sensitivity, (2) The 3-D information matrix
(infrared pump laser frequency, SMM/THz probe frequency, and
time resolved SMM/THz relaxation) can provide orders of
magnitude greater specificity than a sensor that uses only
one of these three dimensions, and (3) The congested and
relatively weak spectra associated with large molecules can
actually be an asset because the usually deleterious effect
of their overlapping spectra can be used to increase signal
strength.},
Key = {Lucia:2007p735}
}
@article{2007JAP...102g3520P,
Author = {Peng, H and Lee, CW and Everitt, HO and Munasinghe, C and Lee, DS and Steckl, AJ},
Title = {Spectroscopic and energy transfer studies of Eu3+ centers in
GaN},
Journal = {Journal of Applied Physics},
Volume = {102},
Number = {7},
Pages = {073520-073520},
Organization = {Department of Physics, Duke University, Durham, North
Carolina 27708, USA},
Institution = {Department of Physics, Duke University, Durham, North
Carolina 27708, USA},
Year = {2007},
Month = {October},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007JAP...102g3520P&link_type=ABSTRACT},
Abstract = {Photoluminescence (PL), photoluminescence excitation (PLE),
and time-resolved PL spectroscopies have been carried out at
room temperature and 86 K on transitions from D25, D15, and
D05 excited states to numerous FJ7 ground states of Eu-doped
GaN films grown by conventional solid-source molecular beam
epitaxy (MBE) and interrupted growth epitaxy MBE. Within the
visible spectral range of 1.8-2.7 eV, 42 spectral features
were observed and assignments were attempted for each
transition. PL and PLE indicate that four Eu3+ centers exist
in the GaN lattice whose relative concentration can be
controlled by the duration of growth interruption. The
energy levels for these four sites are self-consistently
obtained, and time-resolved photoluminescence measurements
reveal details about the radiative and nonradiative
relaxations of excitation among these levels. The data
indicate a near-resonant cross relaxation among these sites.
The D25 and D15 states are observed to decay nonradiatively
by filling the D05 state with characteristic times of 2.4
and 2.8 μs, respectively. The D05 state is found to relax
in a manner that depends slightly on the final state and
dopant site. © 2007 American Institute of
Physics.},
Doi = {10.1063/1.2783893},
Key = {2007JAP...102g3520P}
}
@article{Li:2008p1261,
Author = {li, J and Peng, H and Liu, J and Everitt, HO},
Title = {Facile Gram-Scale Growth of Single-Crystalline
Nanotetrapod-Assembled ZnO through a Rapid
Process},
Journal = {European Journal of Inorganic Chemistry},
Volume = {2008},
Number = {20},
Pages = {3172-3176},
Publisher = {WILEY},
Organization = {Duke Univ, Dept Chem, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Chem, Durham, NC 27708 USA},
Year = {2008},
url = {http://www3.interscience.wiley.com/journal/119814989/abstract?CRETRY=1&SRETRY=0},
Abstract = {From a rapid combustion and catalyst-free method, pure
single-crystalline nanotetrapod-assembled bulk nano-ZnO was
grown on a gram-scale for the first time. The gram-scale
bulk nano-ZnO is synthesized from ZnO powder with great
reliability and repeatability, and also a high conversion
efficiency. All four arms of the nanotetrapods are cone
shaped and grow in the [001] direction. The
photoluminescence properties of the nanotetrapod-assembled
ZnO were studied and a mechanism was suggested for the
growth of the bulk nanotetrapod-assembled ZnO. © Wiley-VCH
Verlag GmbH & Co. KGaA, 2008.},
Language = {English},
Doi = {10.1002/ejic.200701306},
Key = {Li:2008p1261}
}
@article{fds350798,
Author = {Wu, PC and Losurdo, M and Kim, TH and Bruno, G and Brown, AS and Everitt,
HO},
Title = {Novel, real-time measurement of plasmon resonance -
tailoring nanoparticle geometry optically},
Journal = {Optics Infobase Conference Papers},
Year = {2008},
Month = {January},
ISBN = {9781557528612},
url = {http://dx.doi.org/10.1364/oft.2008.jwd36},
Abstract = {We demonstrate novel use of in situ spectroscopic
ellipsometry to probe in real-time metal nanoparticle
deposition. Real-time monitoring of NP assembly plasmon
resonance enables control of NP size via the plasmon
resonance and vice versa.},
Doi = {10.1364/oft.2008.jwd36},
Key = {fds350798}
}
@article{fds331991,
Author = {Wu, PC and Losurdo, M and Kim, TH and Bruno, G and Brown, AS and Everitt,
HO},
Title = {Novel, real-time measurement of plasmon resonance -
tailoring nanoparticle geometry optically},
Journal = {Optics Infobase Conference Papers},
Year = {2008},
Month = {January},
Abstract = {We demonstrate novel use of in situ spectroscopic
ellipsometry to probe in real-time metal nanoparticle
deposition. Real-time monitoring of NP assembly plasmon
resonance enables control of NP size via the plasmon
resonance and vice versa. © 2008 OSA.},
Key = {fds331991}
}
@article{fds331992,
Author = {Wu, PC and Losurdo, M and Kim, TH and Bruno, G and Brown, AS and Everitt,
HO},
Title = {Novel, real-time measurement of plasmon resonance -
tailoring nanoparticle geometry optically},
Journal = {Optics Infobase Conference Papers},
Year = {2008},
Month = {January},
Abstract = {We demonstrate novel use of in situ spectroscopic
ellipsometry to probe in real-time metal nanoparticle
deposition. Real-time monitoring of NP assembly plasmon
resonance enables control of NP size via the plasmon
resonance and vice versa.},
Key = {fds331992}
}
@inproceedings{Avrutin:2008cq,
Author = {Avrutin, V and Reshchikov, M A and Nie, J and Izyumskaya, N and Shimada, R and {\"O}zg{\"u}r, {\"U}mit and Foreman, John
V and Everitt, Henry O and Litton, C and Morko{\c c},
H},
Title = {Effect of ion damage on optical properties of ZnO films
grown by plasma-assisted MBE},
Pages = {68950Y--68950Y--8},
Booktitle = {Zinc Oxide Materials and Devices III},
Publisher = {SPIE},
Year = {2008},
Month = {February},
url = {http://link.aip.org/link/PSISDG/v6895/i1/p68950Y/s1&Agg=doi},
Abstract = {The effect of plasma-induced ion damage on the optical
properties of ZnO films grown by plasma-assisted molecular
beam epitaxy on a-sapphire substrates and
GaN(0001)/c-sapphire templates prepared has been studied
using steady-state and time-resolved photoluminescence. We
observed that the deflecting the ions produced by the RF
oxygen plasma away from substrate results in improved
excitonic emission and modification of the defect-related PL
spectrum. The intensity of the near-band-edge lines in the
photoluminescence spectra from the layers grown with the ion
deflection was found to increase by factors 7 to 20 for the
layers grown on GaN(0001)/c-sapphire at a plasma power of
350 W and by 3 to 4 times for ZnO grown on a-sapphire
substrates at a plasma power of 265 W as compared to the
controls grown without the ion deflection. The yellow-green
spectral range was dominated by different defect bands in
the films grown with and without ion deflection. The effect
of RF power on peak positions of the defect band was studied
for the films grown without ion deflection. For the ZnO
films grown on a-plane sapphire substrates, time-resolved
photoluminescence showed a significant increase in
luminescence decay times both at RT and 89 K. However, for
ZnO on GaN(0001)/c- sapphire substrates, virtually no
improvement in decay time was found at 89 K with only a
moderate increase in decay constant at room
temperature.},
Language = {English},
Doi = {10.1117/12.764132},
Key = {Avrutin:2008cq}
}
@article{Choi:2008ji,
Author = {Choi, S and Kim, TH and Wolter, S and Brown, A and Everitt, HO and Losurdo,
M and Bruno, G},
Title = {Indium adlayer kinetics on the gallium nitride (0001)
surface: Monitoring indium segregation and
precursor-mediated adsorption},
Journal = {Physical Review B},
Volume = {77},
Number = {11},
Pages = {115435},
Publisher = {American Physical Society (APS)},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2008},
Month = {March},
ISSN = {1098-0121},
url = {http://link.aps.org/doi/10.1103/PhysRevB.77.115435},
Abstract = {Indium kinetics and evidence for indium segregation on the
GaN (0001) surface are investigated via in situ
spectroscopic ellipsometry. Indium deposition exhibits two
stable states at coverages of 1.0 and 1.7 ML within the
temperature range of 630-688°C. Formation of each layer is
governed by two kinetic processes: nuclei formation and
nuclei-mediated layer adsorption. The measured desorption
activation energies of nuclei of the first (2.04 eV) and
second (2.33 eV) monolayers are lower than the desorption
activation energies of the aggregated first (2.64 eV) and
second (2.53 eV) monolayers, respectively. This suggests
that adatoms preferentially interact with the nuclei and
laterally aggregate. © 2008 The American Physical
Society.},
Language = {English},
Doi = {10.1103/PhysRevB.77.115435},
Key = {Choi:2008ji}
}
@article{fds318424,
Author = {Avrutin, V and Reshchikov, MA and Nie, J and Izyumskaya, N and Shimada,
R and Özgür, U and Foreman, JV and Everitt, HO and Litton, C and Morkoç,
H},
Title = {Effect of ion damage on optical properties of ZnO films
grown by plasma-assisted MBE},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6895},
Pages = {Y8950-Y8950},
Publisher = {SPIE},
Year = {2008},
Month = {April},
ISBN = {9780819470706},
url = {http://dx.doi.org/10.1117/12.764132},
Abstract = {The effect of plasma-induced ion damage on the optical
properties of ZnO films grown by plasma-assisted molecular
beam epitaxy on a-sapphire substrates and
GaN(0001)/c-sapphire templates prepared has been studied
using steady-state and time-resolved photoluminescence. We
observed that the deflecting the ions produced by the RF
oxygen plasma away from substrate results in improved
excitonic emission and modification of the defect-related PL
spectrum. The intensity of the near-band-edge lines in the
photoluminescence spectra from the layers grown with the ion
deflection was found to increase by factors 7 to 20 for the
layers grown on GaN(0001)/c-sapphire at a plasma power of
350 W and by 3 to 4 times for ZnO grown on a-sapphire
substrates at a plasma power of 265 W as compared to the
controls grown without the ion deflection. The yellow-green
spectral range was dominated by different defect bands in
the films grown with and without ion deflection. The effect
of RF power on peak positions of the defect band was studied
for the films grown without ion deflection. For the ZnO
films grown on a-plane sapphire substrates, time-resolved
photoluminescence showed a significant increase in
luminescence decay times both at RT and 89 K. However, for
ZnO on GaN(0001)/csapphire substrates, virtually no
improvement in decay time was found at 89 K with only a
moderate increase in decay constant at room
temperature.},
Doi = {10.1117/12.764132},
Key = {fds318424}
}
@inproceedings{Wellenius:2008p1268,
Author = {Wellenius, P and Suresh, A and Foreman, JV and Everitt, HO and Muth,
JF},
Title = {A visible transparent electroluminescent europium doped
gallium oxide device},
Journal = {Materials Science and Engineering: B},
Volume = {146},
Number = {1-3},
Pages = {252-255},
Booktitle = {Materials Science And Engineering B-Solid State Materials
For Advanced Technology},
Publisher = {Elsevier BV},
Organization = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27606 USA},
Institution = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27606 USA},
Year = {2008},
Month = {May},
url = {http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TXF-4PDSXKP-2&_user=38557&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000004358&_version=1&_urlVersion=0&_userid=38557&md5=6df7bab5c82e01ed116da32630a218e8},
Abstract = {Beta phase gallium oxide thin films deposited by pulsed
laser deposition are efficient hosts for rare earth metals
such as europium. In this study europium doped gallium oxide
deposited on glass substrates is used to make red (611 nm)
electroluminescent devices that are transparent to the
visible spectrum. The conducting electrodes used are indium
tin oxide (ITO), and a novel indium gallium zinc oxide
(IGZO) layer also deposited by pulsed laser deposition. The
origin of the red emission is the 5D0 to 7F2 transition and
is consistent with photoluminescence and cathodoluminescence
results. The turn on voltage of the device is about 45 V ac,
and the device appears to be robust, operating at elevated
voltages without degradation. © 2007 Elsevier B.V. All
rights reserved.},
Language = {English},
Doi = {10.1016/j.mseb.2007.07.060},
Key = {Wellenius:2008p1268}
}
@article{Glinka:2009p888,
Author = {Glinka, Yuri D and Foreman, John V and Everitt, Henry O and Lee, Don S and Steckl, Andrew J},
Title = {Direct and indirect photoluminescence excitation and
ultraviolet emission from Tm]-doped AlxGa1-xN},
Journal = {Journal of Applied Physics},
Volume = {105},
Number = {8},
Pages = {--},
Organization = {USA, Aviat {\&} Missile RDEC, Redstone Arsenal, AL 35898
USA},
Institution = {USA, Aviat {\&} Missile RDEC, Redstone Arsenal, AL 35898
USA},
Year = {2009},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JAPIAU000105000008083509000001&idtype=cvips&gifs=yes},
Abstract = {We provide experimental evidence for direct and indirect
excitations of photoluminescence (PL) from Tm-doped
AlxGa1-xN of varying Al content. Direct excitation of Tm3+
ions is observed primarily at 85 K through transitions
H-3(6)-> I-1(6), P-3(0), P-3(1), and P-3(2) when these
levels are below the absorption edge of the AlxGa1-xN for a
given Al content. Strong ultraviolet emission at 298 nm
(I-1(6)-> H-3(6)), 355 nm (I-1(6)-> F-3(4)), and 371 nm
(D-1(2)-> H-3(6)), as well as the familiar blue emission at
463 nm (D-1(2)-> F-3(4)), and 479 nm ((1)G(4)-> H-3(6)), is
found to depend sensitively on the Al content, excitation
wavelength (i.e., direct or indirect), excitation type
(continuous wave versus pulsed), and upper state of the
transition. PL excitation spectroscopy and time-integrated
and time-resolved PL spectra are compared to elucidate the
complex energy transfer pathways.},
Language = {English},
Doi = {10.1063/1.3098256},
Key = {Glinka:2009p888}
}
@article{Glinka:2009p1269,
Author = {Glinka, Y D and Everitt, H O and Lee, D S and Steckl, A
J},
Title = {Effect of Tm3+-induced defects on the photoexcitation energy
relaxation in Tm-doped AlxGa1-xN},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {79},
Number = {11},
Pages = {--},
Organization = {Natl Acad Sci Ukraine, Inst Phys, UA-03028 Kiev,
Ukraine},
Institution = {Natl Acad Sci Ukraine, Inst Phys, UA-03028 Kiev,
Ukraine},
Year = {2009},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRBMDO000079000011113202000001&idtype=cvips&gifs=yes},
Abstract = {We provide evidence that the Tm3+-induced defects in
Tm-doped AlxGa1-xN hosts play a major role in the
nonradiative transfer of the excitation energy from the
I-1(6) state to the D-1(2) state of Tm3+ ions from which the
most efficient photoluminescence (PL) transition (465 nm)
occurs. Once the concentration of the Tm3+-induced defects
decreases with increasing x, the PL transitions starting
from the I-1(6) state (298, 357, 395, 530, and 785 nm) may
be significantly enhanced. It is shown that the indirect
excitation of the I-1(6) state results from the Auger-type
energy transfer due to the nonradiative band-to-band
recombinations in the AlxGa1-xN host of a given x. In
contrast, the PL transitions starting from the (1)G(4) level
(479 and 807 nm) can be excited through either an indirect
or a direct regime. In both cases the (1)G(4) level is
populated by the radiative relaxation of the higher energy
excited states I-1(6), P-3(0), P-3(1), and P-3(2) of Tm3+
ions.},
Language = {English},
Doi = {10.1103/PhysRevB.79.113202},
Key = {Glinka:2009p1269}
}
@article{Choi:2009iu,
Author = {Choi, Soojeong and Kim, Tong-Ho and Wu, Pae and Brown, April and Everitt, Henry O and Losurdo, Maria and Bruno,
Giovanni},
Title = {Band bending and adsorption/desorption kinetics on N-polar
GaN surfaces},
Journal = {Journal of Vacuum Science {\&} Technology B:
Microelectronics and Nanometer Structures},
Volume = {27},
Pages = {107},
Year = {2009},
Month = {January},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009JVSTB..27..107C&link_type=EJOURNAL},
Abstract = {Not Available},
Doi = {10.1116/1.3054345},
Key = {Choi:2009iu}
}
@article{Glinka:2009p1730,
Author = {Glinka, Y D and Everitt, Henry O and Muth, John F and Shahbazyan, T V and Roberts, J and Rajagopal, P and Cook, J and Piner, E and Linthicum, K},
Title = {Photoluminescence from surface GaN/AlGaN quantum wells:
Effect of the surface states},
Journal = {arXiv},
Volume = {cond-mat.mtrl-sci},
Year = {2009},
Month = {January},
url = {http://arxiv.org/abs/0905.1972v1},
Keywords = {cond-mat.mtrl-sci},
Abstract = {We report on photoluminescence (PL) measurements at 85 K for
GaN/AlGaN surface quantum wells (SQW's) with a width in the
range of 1.51-2.9 nm. The PL spectra show a redshift with
decreasing SQW width, in contrast to the blueshift normally
observed for conventional GaN QW's of the same width. The
effect is attributed to a strong coupling of SQW confined
exciton states with surface acceptors. The PL hence
originates from the recombination of surface-acceptor-bound
excitons. Two types of acceptors were identified.},
Key = {Glinka:2009p1730}
}
@article{Wu:2009cm,
Author = {Wu, PC and Losurdo, M and Kim, TH and Giangregorio, M and Bruno, G and Everitt, HO and Brown, AS},
Title = {Plasmonic Gallium Nanoparticles on Polar Semiconductors:
Interplay between Nanoparticle Wetting, Localized Surface
Plasmon Dynamics, and Interface Charge},
Journal = {Langmuir : the Acs Journal of Surfaces and
Colloids},
Volume = {25},
Number = {2},
Pages = {924-930},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2009},
Month = {January},
ISSN = {0743-7463},
url = {http://links.isiglobalnet2.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=mekentosj&SrcApp=Papers&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000262431100040},
Abstract = {Ga nanoparticles supported on large band gap semiconductors
like SiC, GaN, and ZnO are interesting for plasmon-enhanced
UV-emitting solid-state devices. We investigate the
influence of the polarity of the SiC, GaN, and ZnO wurtzite
semiconductors on the wetting of Ga nanoparticles and on the
resulting surface plasmon resonance (SPR) by exploiting real
time plasmonic ellipsometry. The interface potential between
polar semiconductors (SiC, GaN, and ZnO) and plasmonic
nanoparticles (gallium) is shown to influence nanoparticle
formation dynamics, geometry, and consequently the SPR
wavelength. We invoke the Lippman electrowetting framework
to elucidate the mechanisms controlling nanoparticle
dynamics and experimentally demonstrate that the charge
transfer at the Ga nanoparticle/polar semiconductor
interface is an intrinsic method for tailoring the
nanoparticle plasmon resonance. Therefore, the present data
demonstrate that for supported nanoparticles, surface and
interface piezoelectric charge of polar semiconductors also
affects SPR along with the well-known effect of the media
refractive index.},
Language = {English},
Doi = {10.1021/la802678y},
Key = {Wu:2009cm}
}
@article{Wu:2009cma,
Author = {Wu, Pae C and Losurdo, Maria and Kim, Tong-Ho and Giangregorio, Michelaria and Bruno, Giovanni and Everitt,
Henry O and Brown, April S},
Title = {Plasmonic Gallium Nanoparticles on Polar Semiconductors:
Interplay between Nanoparticle Wetting, Localized Surface
Plasmon Dynamics, and Interface Charge},
Journal = {Langmuir},
Volume = {25},
Number = {2},
Pages = {924--930},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2009},
Month = {January},
url = {http://links.isiglobalnet2.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=mekentosj&SrcApp=Papers&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000262431100040},
Abstract = {Ga nanoparticles supported on large band gap semiconductors
like SiC, GaN, and ZnO are interesting for plasmon-enhanced
UV-emitting solid-state devices. We investigate the
influence of the polarity of the SiC, GaN, and ZnO wurtzite
semiconductors on the wetting of Ga nanoparticles and on the
resulting surface plasmon resonance (SPR) by exploiting real
time plasmonic ellipsometry. The interface potential between
polar semiconductors (SiC, GaN, and ZnO) and plasmonic
nanoparticles (gallium) is shown to influence nanoparticle
formation dynamics, geometry, and consequently the SPR
wavelength. We invoke the Lippman electrowetting framework
to elucidate the mechanisms controlling nanoparticle
dynamics and experimentally demonstrate that the charge
transfer at the Ga nanoparticle/polar semiconductor
interface is an intrinsic method for tailoring the
nanoparticle plasmon resonance. Therefore, the present data
demonstrate that for supported nanoparticles, surface and
interface piezoelectric charge of polar semiconductors also
affects SPR along with the well-known effect of the media
refractive index.},
Language = {English},
Doi = {10.1021/la802678y},
Key = {Wu:2009cma}
}
@article{Choi:2009p1804,
Author = {Choi, S and Kim, TH and Wu, P and Brown, A and Everitt, HO and Losurdo, M and Bruno, G},
Title = {Band bending and adsorption/desorption kinetics on N-polar
GaN surfaces},
Journal = {Journal of Vacuum Science & Technology. B, Microelectronics
and Nanometer Structures : Processing, Measurement, and
Phenomena : an Official Journal of the American Vacuum
Society},
Volume = {27},
Number = {1},
Pages = {107-112},
Publisher = {American Vacuum Society},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2009},
Month = {February},
ISSN = {1071-1023},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JVTBD9000027000001000107000001&idtype=cvips&gifs=yes},
Abstract = {Highly reactive N-polar [000-1] GaN surfaces were analyzed
using spectroscopic ellipsometry. Following exposure to air,
observed changes in the pseudodielectric function near the
GaN band edge indicate that surface contamination reduces
the band bending. A subsequent Ga adsorption/desorption
experiment on pristine N-polar GaN indicates that it
contains a mixture of Ga-terminated and N-terminated
surfaces. During deposition, Ga adatoms preferentially bond
to the dangling bonds on the N-terminated surface: the
measured 3.19 eV desorption activation energy equals the
Ga-N decomposition energy. Further deposition forms a 1 ML
Ga wetting layer whose 2.78 eV desorption activation energy
is comparable to the Ga sublimation energy. © 2009 American
Vacuum Society.},
Language = {English},
Doi = {10.1116/1.3054345},
Key = {Choi:2009p1804}
}
@article{Wellenius:2009p3824,
Author = {Wellenius, Patrick and Muth, John F and Wu, Pae C and Everitt, Henry O and Smith, Eric R},
Title = {Effect of Oxygen Pressure on the Structure and Luminescence
of Europium Doped Gadolinium Oxide Thin Films},
Journal = {American Physical Society},
Pages = {21015},
Year = {2009},
Month = {March},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009APS..MARX21015W&link_type=ABSTRACT},
Abstract = {Gadolinium oxide has found uses as a dielectric or
passivation layer for novel III-V materials and devices, but
more recently has been the subject of study as a rare-earth
host. It is believed that Gd2O3 makes a good host for these
dopants due to the similarity in ionic radii between the
gadolinium ion and the rare-earth dopants. The reported long
radiative lifetimes of rare earth dopants in this material
make it interesting for optically pumped laser materials. In
this study, europium-doped gadolinium oxide (Eu:Gd2O3)
polycrystalline thin films were deposited on sapphire
substrates by pulsed laser deposition at 5 and 50 mTorr
oxygen pressure. Changes in the crystal structure were
observed by x-ray diffraction and photoluminescence.
Low-temperature photoluminescence spectra of the ^5D0-^7F0
and ^7F2 transitions in the europium ion were recorded with
high resolution. Because the ^5D0-^7F0 transition in
europium is not subject to fine structure splitting, it
provides a useful mechanism for investigation of the local
environment. The ^5D0-^7F2 transition is of interest as it
results in the most intense emission, making europium doped
material useful for red light-emitting phosphors. Radiative
lifetimes of the observed transitions are also
reported.},
Key = {Wellenius:2009p3824}
}
@article{2009PhRvB..79k3202G,
Author = {Glinka, Y D and Everitt, Henry O and Lee, D S and Steckl, A
J},
Title = {Effect of Tm3+ -induced defects on the photoexcitation
energy relaxation in Tm-doped AlxGa1-xN},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {79},
Number = {11},
Pages = {113202},
Organization = {Institute of Physics, National Academy of Sciences of
Ukraine, Kiev 03028, Ukraine},
Institution = {Institute of Physics, National Academy of Sciences of
Ukraine, Kiev 03028, Ukraine},
Year = {2009},
Month = {March},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009PhRvB..79k3202G&link_type=ABSTRACT},
Abstract = {We provide evidence that the Tm3+ -induced defects in
Tm-doped AlxGa1-xN hosts play a major role in the
nonradiative transfer of the excitation energy from the I16
state to the D12 state of Tm3+ ions from which the most
efficient photoluminescence (PL) transition (465 nm) occurs.
Once the concentration of the Tm3+ -induced defects
decreases with increasing x , the PL transitions starting
from the I16 state (298, 357, 395, 530, and 785 nm) may be
significantly enhanced. It is shown that the indirect
excitation of the I16 state results from the Auger-type
energy transfer due to the nonradiative band-to-band
recombinations in the AlxGa1-xN host of a given x . In
contrast, the PL transitions starting from the G14 level
(479 and 807 nm) can be excited through either an indirect
or a direct regime. In both cases the G14 level is populated
by the radiative relaxation of the higher energy excited
states I16 , P30 , P31 , and P32 of Tm3+
ions.},
Doi = {10.1103/PhysRevB.79.113202},
Key = {2009PhRvB..79k3202G}
}
@article{fds314087,
Author = {Glinka, YD and Everitt, HO and Lee, DS and Steckl,
AJ},
Title = {Effect of Tm3+ -induced defects on the photoexcitation
energy relaxation in Tm-doped Alx Ga1-x N},
Journal = {Physical Review B},
Volume = {79},
Number = {11},
Publisher = {American Physical Society (APS)},
Year = {2009},
Month = {March},
ISSN = {1098-0121},
url = {http://dx.doi.org/10.1103/PhysRevB.79.113202},
Abstract = {We provide evidence that the Tm3+ -induced defects in
Tm-doped Alx Ga1-x N hosts play a major role in the
nonradiative transfer of the excitation energy from the I1 6
state to the D1 2 state of Tm3+ ions from which the most
efficient photoluminescence (PL) transition (465 nm) occurs.
Once the concentration of the Tm3+ -induced defects
decreases with increasing x, the PL transitions starting
from the I1 6 state (298, 357, 395, 530, and 785 nm) may be
significantly enhanced. It is shown that the indirect
excitation of the I1 6 state results from the Auger-type
energy transfer due to the nonradiative band-to-band
recombinations in the Alx Ga1-x N host of a given x. In
contrast, the PL transitions starting from the G1 4 level
(479 and 807 nm) can be excited through either an indirect
or a direct regime. In both cases the G1 4 level is
populated by the radiative relaxation of the higher energy
excited states I1 6, P3 0, P3 1, and P3 2 of Tm3+ ions. ©
2009 The American Physical Society.},
Doi = {10.1103/PhysRevB.79.113202},
Key = {fds314087}
}
@article{Li:2009p1264,
Author = {Li, J and Zhang, Q and Peng, H and Everitt, HO and Qin, L and Liu,
J},
Title = {Diameter-controlled vapor-solid epitaxial growth and
properties of aligned ZnO nanowire arrays},
Journal = {The Journal of Physical Chemistry C},
Volume = {113},
Number = {10},
Pages = {3950-3954},
Publisher = {American Chemical Society (ACS)},
Organization = {Duke Univ, Dept Chem, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Chem, Durham, NC 27708 USA},
Year = {2009},
Month = {March},
ISSN = {1932-7447},
url = {http://pubs.acs.org/doi/abs/10.1021/jp8083716},
Abstract = {A facile, template-free method was used to grow large areas
of well-aligned ZnO nanowire arrays on amorphous SiO 2
substrates. The arrays are composed of vertically aligned,
single-crystalline, wurtzitic [001] ZnO nanowires whose
diameters were easily controlled by growth temperature,
adjusted by changing the distance between the substrate and
the precursor material in the growth chamber. A vapor-solid
epitaxial growth mechanism is proposed by which ZnO
nanocrystals, nucleated on a NiO catalytic film, seed the
growth of the ZnO nanowires. Photoluminescence spectra
indicate broad visible wavelength emission, likely caused by
near surface traps, whose intensity relative to band edge
ultraviolet emission grows as nanowire radii decrease. UV
photoconductivity measured for individual ZnO nanowire
devices demonstrates their potential as a UV light
nanosensor. © 2009 American Chemical Society.},
Language = {English},
Doi = {10.1021/jp8083716},
Key = {Li:2009p1264}
}
@article{2009JAP...105h3509G,
Author = {Glinka, Yuri D and Foreman, John V and Everitt, Henry O and Lee, Don S and Steckl, Andrew J},
Title = {Direct and indirect photoluminescence excitation and
ultraviolet emission from Tm-doped AlxGa1-xN},
Journal = {Journal of Applied Physics},
Volume = {105},
Number = {8},
Pages = {3509},
Organization = {U.S. Army Aviation and Missile RDEC, Redstone Arsenal,
Alabama 35898, USA; Nano and Micro Devices Center,
University of Alabama in Huntsville, Huntsville, Alabama
35899, USA},
Institution = {U.S. Army Aviation and Missile RDEC, Redstone Arsenal,
Alabama 35898, USA; Nano and Micro Devices Center,
University of Alabama in Huntsville, Huntsville, Alabama
35899, USA},
Year = {2009},
Month = {April},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009JAP...105h3509G&link_type=ABSTRACT},
Abstract = {We provide experimental evidence for direct and indirect
excitations of photoluminescence (PL) from Tm-doped
AlxGa1-xN of varying Al content. Direct excitation of Tm3+
ions is observed primarily at 85 K through transitions
3H6-->1I6, 3P0, 3P1, and 3P2 when these levels are below the
absorption edge of the AlxGa1-xN for a given Al content.
Strong ultraviolet emission at 298 nm (1I6-->3H6), 355 nm
(1I6-->3F4), and 371 nm (1D2-->3H6), as well as the familiar
blue emission at 463 nm (1D2-->3F4), and 479 nm (1G4-->3H6),
is found to depend sensitively on the Al content, excitation
wavelength (i.e., direct or indirect), excitation type
(continuous wave versus pulsed), and upper state of the
transition. PL excitation spectroscopy and time-integrated
and time-resolved PL spectra are compared to elucidate the
complex energy transfer pathways.},
Doi = {10.1063/1.3098256},
Key = {2009JAP...105h3509G}
}
@article{fds314134,
Author = {Glinka, YD and Foreman, JV and Everitt, HO and Lee, DS and Steckl,
AJ},
Title = {Direct and indirect photoluminescence excitation and
ultraviolet emission from Tm-doped AlxGa1-xN},
Journal = {Journal of Applied Physics},
Volume = {105},
Number = {8},
Pages = {083509-083509},
Publisher = {AIP Publishing},
Year = {2009},
Month = {May},
ISSN = {0021-8979},
url = {http://dx.doi.org/10.1063/1.3098256},
Abstract = {We provide experimental evidence for direct and indirect
excitations of photoluminescence (PL) from Tm-doped
AlxGa1-xN of varying Al content. Direct excitation of Tm3+
ions is observed primarily at 85 K through transitions 3H6
→ 1I 6, 3P0, 3P1, and 3P2 when these levels are below the
absorption edge of the AlxGa1-xN for a given Al content.
Strong ultraviolet emission at 298 nm (1I6 → 3H6), 355 nm
(1I6 → 3F4), and 371 nm (1D2 → 3H6), as well as the
familiar blue emission at 463 nm (1D2 → 3F4), and 479 nm
(1G4 → 3H6), is found to depend sensitively on the Al
content, excitation wavelength (i.e., direct or indirect),
excitation type (continuous wave versus pulsed), and upper
state of the transition. PL excitation spectroscopy and
time-integrated and time-resolved PL spectra are compared to
elucidate the complex energy transfer pathways. © 2009
American Institute of Physics.},
Doi = {10.1063/1.3098256},
Key = {fds314134}
}
@inproceedings{Foreman:ee,
Author = {Foreman, JV and Everitt, HO and Yang, J and Liu, J},
Title = {Carrier dynamics and photoexcited emission efficiency of
ZnO:Zn phosphor powders},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7214},
Pages = {721405--721405--12},
Booktitle = {Ultrafast Phenomena in Semiconductors and Nanostructure
Materials XIII},
Publisher = {SPIE},
Year = {2009},
Month = {June},
url = {http://link.aip.org/link/PSISDG/v7214/i1/p721405/s1&Agg=doi},
Abstract = {Nonstoichiometric ZnO with an excess of Zn atoms (ZnO:Zn)
has a long history of use as a green/monochrome phosphor in
electron-excited vacuum fluorescent and field emission
displays. The advent of ultraviolet lasers and light
emitting diodes presents the possibility of photoexciting
the highly efficient, defect-related green emission in
ZnO:Zn. Here we study experimentally the time-integrated
quantum efficiency and the time-resolved photoluminescence
decays of both near band edge and defect emissions in
unannealed (ZnO) and annealed (ZnO:Zn) nanoparticles under
femtosecond excitation. A comparison of results using
one-photon excitation (excitation primarily near the
particlés surface) versus two-photon excitation (uniform
excitation throughout the particlés volume) elucidates how
the quantum efficiencies depend on material properties, such
as the spatial distributions of radiative and nonradiative
defects, and on optical effects, such as reabsorption. ©
2009 SPIE.},
Doi = {10.1117/12.811561},
Key = {Foreman:ee}
}
@article{Foreman:2009vi,
Author = {Foreman, John V and Everitt, Henry O and Yang, J H and McNicholas, T and Liu, J P},
Title = {Effects of reabsorption and spatial trap distributions on
the radiative quantum efficiencies of ZnO},
Journal = {arXiv},
Organization = {Department of Physics, Duke University},
Institution = {Department of Physics, Duke University},
Year = {2009},
Month = {August},
url = {http://arxiv.org/abs/0904.4201},
Abstract = {Ultrafast time-resolved photoluminescence spectroscopy
following one- and two-photon excitation of ZnO powder is
used to gain unprecedented insight into the surprisingly
high external quantum efficiency of its "green" defect
emission band. The role of exciton diffusion, the effects of
reabsorption, and the spatial distributions of radiative and
nonradiative traps are comparatively elucidated for the
ultraviolet excitonic and "green" defect emission bands in
both unannealed, nanometer-sized ZnO powders and annealed,
micrometer-sized ZnO:Zn powders. We find that the primary
mechanism limiting quantum efficiency is surface
recombination because of the high density of nonradiative
surface traps in these powders. It is found that unannealed
ZnO has a high density of bulk nonradiative traps as well,
but the annealing process reduces the density of these bulk
traps while simultaneously creating a high density of
green-emitting defects near the particle surface. The data
are discussed in the context of a simple rate equation model
that accounts for the quantum efficiencies of both emission
bands. The results indicate how defect engineering could
improve the efficiency of ultraviolet-excited ZnO:Zn-based
white light phosphors.},
Key = {Foreman:2009vi}
}
@article{Glinka:2009p4820,
Author = {Glinka, YD and Shahbazyan, TV and Everitt, HO and Roberts, J and Rajagopal, P and Cook, J and Piner, E and Linthicum,
K},
Title = {Effect of the surface states on photoluminescence from
surface GaN/Al 0.2Ga0.8N quantum
wells},
Journal = {Epl (Europhysics Letters)},
Volume = {87},
Number = {4},
Pages = {47007-47007},
Publisher = {IOP Publishing},
Organization = {Natl Acad Sci Ukraine, Inst Phys, UA-03028 Kiev,
Ukraine},
Institution = {Natl Acad Sci Ukraine, Inst Phys, UA-03028 Kiev,
Ukraine},
Year = {2009},
Month = {August},
ISSN = {0295-5075},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000270146400022&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We report on photoluminescence (PL) measurements at 85 K for
GaN/Al 0.2Ga0.8N surface quantum wells (SQWs) with a width
in the range of 1.51-2.9 nm. The PL spectra show a redshift
with decreasing SQW width, in contrast to the blueshift
normally observed for conventional GaN QWs of the same
width. The effect is attributed to a strong coupling of SQW
confined exciton states with surface acceptors. The PL hence
originates from the recombination of surface-acceptor-bound
(A0sXA) excitons. Two types of acceptors were identified. ©
2009 Europhysics Letters Association.},
Language = {English},
Doi = {10.1209/0295-5075/87/47007},
Key = {Glinka:2009p4820}
}
@article{Wu:2009p4819,
Author = {Wu, PC and Khoury, CG and Kim, T-H and Yang, Y and Losurdo, M and Bianco,
GV and Vo-Dinh, T and Brown, AS and Everitt, HO},
Title = {Demonstration of surface-enhanced Raman scattering by
tunable, plasmonic gallium nanoparticles.},
Journal = {Journal of the American Chemical Society},
Volume = {131},
Number = {34},
Pages = {12032-12033},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2009},
Month = {September},
ISSN = {0002-7863},
url = {http://pubs.acs.org/doi/abs/10.1021/ja903321z},
Abstract = {Size-controlled gallium nanoparticles deposited on sapphire
were explored as alternative substrates to enhance Raman
spectral signatures. Gallium's resilience following
oxidation is inherently advantageous in comparison with
silver for practical ex vacuo nonsolution applications. Ga
nanoparticles were grown using a simple molecular beam
epitaxy-based fabrication protocol, and monitoring their
corresponding surface plasmon resonance energy through in
situ spectroscopic ellipsometry allowed the nanoparticles to
be easily controlled for size. The Raman spectra obtained
from cresyl fast violet (CFV) deposited on substrates with
differing mean nanoparticle sizes represent the first
demonstration of enhanced Raman signals from reproducibly
tunable self-assembled Ga nanoparticles. Nonoptimized
aggregate enhancement factors of approximately 80 were
observed from the substrate with the smallest Ga
nanoparticles for CFV dye solutions down to a dilution of 10
ppm.},
Language = {English},
Doi = {10.1021/ja903321z},
Key = {Wu:2009p4819}
}
@article{fds331990,
Author = {Phillips, DJ and Smith, ER and Luo, H and Wellinius, P and Muth, JF and Everitt, HO and Foreman, JV},
Title = {The potential of wide band-gap semiconductor materials in
laser induced semiconductor switches},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7311},
Publisher = {SPIE},
Year = {2009},
Month = {September},
ISBN = {9780819475770},
url = {http://dx.doi.org/10.1117/12.818741},
Abstract = {Laser induced Semiconductor Switches (LSS), comprised of a
gap antenna deposited on a semiconductor substrate and
photoexcited by a pulsed laser, are the primary source of
THz radiation utilized in time-domain spectroscopy (TDS).
THz-TDS applications such as standoff detection and imaging
would greatly benefit from greater amounts of power coupled
into free space radiation from these sources. The most
common LSS device is based on low temperature-grown (LT)
GaAs photoexcited by Ti:sapphire lasers, but its power
performance is fundamentally limited by low breakdown
voltage. By contrast, wide band-gap semiconductor-based LSS
devices have much higher breakdown voltage and could provide
higher radiant power efficiency but must be photoexcited
blue or ultraviolet pulsed lasers. Here we report an
experimental and theoretical study of 10 wide band-gap
semiconductor LSS host materials: traditional semiconductors
GaN, SiC, and ZnO, both pristine and with various dopants
and alloys, including ternary and quaternary materials MgZnO
and InGaZnO. The objective of this study was to identify the
wide bandgap hosts with the greatest promise for LSS devices
and compare their performance with LT-GaAs. From this effort
three materials, Fe:GaN, MgZnO and Te:ZnO, were identified
as having great potential as LSS devices because of their
band-gap coincidence with frequency multiplied Ti:Sapphire
lasers, increased thermal conductivity and higher breakdown
voltage compared to LT-GaAs, as well as picoseconds scale
recombination times. © 2009 SPIE.},
Doi = {10.1117/12.818741},
Key = {fds331990}
}
@article{Lantz:2009p4821,
Author = {Lantz, KR and Pate, R and Stiff Roberts and AD and Duffell, AG and Smith,
ER and Everitt, HO},
Title = {Comparison of conjugated polymer deposition techniques by
photoluminescence spectroscopy},
Journal = {Journal of Vacuum Science and Technology
B},
Volume = {27},
Number = {5},
Pages = {2227-2231},
Publisher = {American Vacuum Society},
Organization = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Institution = {Duke Univ, Dept Elect {\&} Comp Engn, Durham, NC 27708
USA},
Year = {2009},
Month = {October},
url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JVTBD9000027000005002227000001&idtype=cvips&gifs=yes},
Abstract = {The effects of various deposition techniques on the
photoluminescence spectra of the conjugated polymer
poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-(1-cyanovinylene)
phenylene] (MEH-CN-PPV) are investigated. Photoluminescence
spectroscopy provides insight to the internal morphology of
organic thin films through the identification of interchain
or intrachain recombination peaks. Thin films were deposited
on glass substrates by drop casting, spin casting, and
resonant-infrared matrix-assisted pulsed laser evaporation
(RIR-MAPLE) and were compared to the photoluminescence of
the polymer in solution. The photoluminescence measurements
reported in this article demonstrate that samples deposited
by evaporative RIR-MAPLE have an internal morphology similar
to that of MEH-CN-PPV in solution, leading to an enhancement
of intrachain transitions in the conjugated
polymer.},
Language = {English},
Doi = {10.1116/1.3222855},
Key = {Lantz:2009p4821}
}
@article{DeLucia:2009p1263,
Author = {De Lucia and FC and Petkie, DT and Everitt, HO},
Title = {A double resonance approach to submillimeter/terahertz
remote sensing at atmospheric pressure},
Journal = {Ieee Journal of Quantum Electronics},
Volume = {45},
Number = {2},
Pages = {163-170},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Organization = {Ohio State Univ, Dept Phys, Columbus, OH 43210
USA},
Institution = {Ohio State Univ, Dept Phys, Columbus, OH 43210
USA},
Year = {2009},
Month = {December},
ISSN = {0018-9197},
url = {http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=4721654},
Abstract = {The remote sensing of gases in complex mixtures at
atmospheric pressure is a challenging problem and much
attention has been paid to it. The most fundamental
difference between this application and highly successful
astrophysical and upper atmospheric remote sensing is the
line width associated with atmospheric pressure broadening,
∼ 5 GHz in all spectral regions. In this paper, we discuss
quantitatively a new approach that would use a short pulse
infrared laser to modulate the submillimeter/terahertz
(SMM/THz) spectral absorptions on the time scale of
atmospheric relaxation. We show that such a scheme has three
important attributes. 1) The time resolved pump makes it
possible and efficient to separate signal from atmospheric
and system clutter, thereby gaining as much as a factor of
10a in sensitivity. 2) The 3-D information matrix (infrared
pump laser frequency, SMM/THz probe frequency, and time
resolved SMM/THz relaxation) can provide orders of magnitude
greater specificity than a sensor that uses only one of
these three dimensions. 3) The congested and relatively weak
spectra associated with large molecules can actually be an
asset because the usually deleterious effect of their
overlapping spectra can be used to increase signal strength.
© 2008 IEEE.},
Language = {English},
Doi = {10.1109/JQE.2008.912473},
Key = {DeLucia:2009p1263}
}
@article{Wellenius:2010p5574,
Author = {Wellenius, P and Smith, E R and LeBoeuf, S M and Everitt, H
O and Muth, J F},
Title = {Optimal composition of europium gallium oxide thin films for
device applications},
Journal = {Journal of Applied Physics},
Volume = {107},
Number = {10},
Pages = {--},
Organization = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27695 USA},
Institution = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27695 USA},
Year = {2010},
url = {http://jap.aip.org/japiau/v107/i10/p103111_s1},
Abstract = {Europium gallium oxide (EuxGa1-x)(2)O-3 thin films were
deposited on sapphire substrates by pulsed laser deposition
with varying Eu content from x=2.4 to 20 mol %. The optical
and physical effects of high europium concentration on these
thin films were studied using photoluminescence (PL)
spectroscopy, x-ray diffraction (XRD), and Rutherford
backscattering spectrometry. PL spectra demonstrate that
emission due to the D-5(0) to F-7(J) transitions in Eu3+
grows linearly with Eu content up to 10 mol %. Time-resolved
PL indicates decay parameters remain similar for films with
up to 10 mol % Eu. At 20 mol %, however, PL intensity
decreases substantially and PL decay accelerates, indicative
of parasitic energy transfer processes. XRD shows films to
be polycrystalline and beta-phase for low Eu compositions.
Increasing Eu content beyond 5 mol % does not continue to
modify the film structure and thus, changes in PL spectra
and decay cannot be attributed to structural changes in the
host. These data indicate the optimal doping for
optoelectronic devices based on (EuxGa1-x)(2)O-3 thin films
is between 5 and 10 mol %. (C) 2010 American Institute of
Physics. [doi:10.1063/1.3319670]},
Language = {English},
Doi = {10.1063/1.3319670},
Key = {Wellenius:2010p5574}
}
@article{2010PhRvB..81k5318F,
Author = {Foreman, John V and Everitt, Henry O and Yang, J and McNicholas, T and Liu, J},
Title = {Effects of reabsorption and spatial trap distributions on
the radiative quantum efficiencies of ZnO},
Journal = {Physical Review B (Condensed Matter and Materials
Physics)},
Volume = {81},
Number = {1},
Pages = {115318},
Organization = {Department of Physics, Duke University, Durham, North
Carolina 27708, USA and U.S. Army Aviation and Missile
Research, Development, and Engineering Center, Redstone
Arsenal, Alabama 35898, USA},
Institution = {Department of Physics, Duke University, Durham, North
Carolina 27708, USA and U.S. Army Aviation and Missile
Research, Development, and Engineering Center, Redstone
Arsenal, Alabama 35898, USA},
Year = {2010},
Month = {March},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010PhRvB..81k5318F&link_type=ABSTRACT},
Abstract = {Ultrafast time-resolved photoluminescence spectroscopy
following one- and two-photon excitations of ZnO powder is
used to gain unprecedented insight into the surprisingly
high external quantum efficiency of its ``green'' defect
emission band. The role of exciton diffusion, the effects of
reabsorption, and the spatial distributions of radiative and
nonradiative traps are comparatively elucidated for the
ultraviolet excitonic and ``green'' defect emission bands in
both unannealed nanometer-sized ZnO powders and annealed
micrometer-sized ZnO:Zn powders. We find that the primary
mechanism limiting quantum efficiency is surface
recombination because of the high density of nonradiative
surface traps in these powders. It is found that unannealed
ZnO has a high density of bulk nonradiative traps as well,
but the annealing process reduces the density of these bulk
traps while simultaneously creating a high density of
green-emitting defects near the particle surface. The data
are discussed in the context of a simple rate equation model
that accounts for the quantum efficiencies of both emission
bands. The results indicate how defect engineering could
improve the efficiency of ultraviolet-excited ZnO:Zn-based
white light phosphors.},
Doi = {10.1103/PhysRevB.81.115318},
Key = {2010PhRvB..81k5318F}
}
@article{Foreman:2010p5575,
Author = {Foreman, JV and Everitt, HO and Yang, J and McNicholas, T and Liu,
J},
Title = {Effects of reabsorption and spatial trap distributions on
the radiative quantum efficiencies of ZnO},
Journal = {Physical Review B},
Volume = {81},
Number = {11},
Pages = {--},
Publisher = {American Physical Society (APS)},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2010},
Month = {March},
ISSN = {1098-0121},
url = {http://hdl.handle.net/10161/3240 Duke open
access},
Abstract = {Ultrafast time-resolved photoluminescence spectroscopy
following one- and two-photon excitations of ZnO powder is
used to gain unprecedented insight into the surprisingly
high external quantum efficiency of its "green" defect
emission band. The role of exciton diffusion, the effects of
reabsorption, and the spatial distributions of radiative and
nonradiative traps are comparatively elucidated for the
ultraviolet excitonic and "green" defect emission bands in
both unannealed nanometer-sized ZnO powders and annealed
micrometer-sized ZnO:Zn powders. We find that the primary
mechanism limiting quantum efficiency is surface
recombination because of the high density of nonradiative
surface traps in these powders. It is found that unannealed
ZnO has a high density of bulk nonradiative traps as well,
but the annealing process reduces the density of these bulk
traps while simultaneously creating a high density of
green-emitting defects near the particle surface. The data
are discussed in the context of a simple rate equation model
that accounts for the quantum efficiencies of both emission
bands. The results indicate how defect engineering could
improve the efficiency of ultraviolet-excited ZnO:Zn-based
white light phosphors. © 2010 The American Physical
Society.},
Language = {English},
Doi = {10.1103/PhysRevB.81.115318},
Key = {Foreman:2010p5575}
}
@article{2010JAP...107j3111W,
Author = {Wellenius, P and Smith, ER and Leboeuf, SM and Everitt, HO and Muth,
JF},
Title = {Optimal composition of europium gallium oxide thin films for
device applications},
Journal = {Journal of Applied Physics},
Volume = {107},
Number = {10},
Pages = {103111-103111},
Publisher = {AIP Publishing},
Organization = {Department of Electrical and Computer Engineering, North
Carolina State University, Raleigh, North Carolina 27695,
USA},
Institution = {Department of Electrical and Computer Engineering, North
Carolina State University, Raleigh, North Carolina 27695,
USA},
Year = {2010},
Month = {May},
ISSN = {0021-8979},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010JAP...107j3111W&link_type=ABSTRACT},
Abstract = {Europium gallium oxide (Eux Ga1-x) 2 O3 thin films were
deposited on sapphire substrates by pulsed laser deposition
with varying Eu content from x=2.4 to 20 mol %. The optical
and physical effects of high europium concentration on these
thin films were studied using photoluminescence (PL)
spectroscopy, x-ray diffraction (XRD), and Rutherford
backscattering spectrometry. PL spectra demonstrate that
emission due to the D5 0 to F7 J transitions in Eu3+ grows
linearly with Eu content up to 10 mol %. Time-resolved PL
indicates decay parameters remain similar for films with up
to 10 mol % Eu. At 20 mol %, however, PL intensity decreases
substantially and PL decay accelerates, indicative of
parasitic energy transfer processes. XRD shows films to be
polycrystalline and beta-phase for low Eu compositions.
Increasing Eu content beyond 5 mol % does not continue to
modify the film structure and thus, changes in PL spectra
and decay cannot be attributed to structural changes in the
host. These data indicate the optimal doping for
optoelectronic devices based on (Eux Ga1-x) 2 O3 thin films
is between 5 and 10 mol %. © 2010 American Institute of
Physics.},
Doi = {10.1063/1.3319670},
Key = {2010JAP...107j3111W}
}
@inproceedings{Heimbeck:2010cy,
Author = {Heimbeck, MS and Everitt, HO and Taylor, K and Davis, C and Hamilton, E and Thomas, DE and Reardon, PJ and Hesler, J},
Title = {Instrumentation for beam profiling in the terahertz
regime},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7671},
Pages = {76710J--76710J--12},
Booktitle = {Terahertz Physics, Devices, and Systems IV: Advanced
Applications in Industry and Defense},
Publisher = {SPIE},
Year = {2010},
Month = {June},
ISBN = {9780819481351},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000284871000014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {The standalone, portable Terahertz (THz) Imaging Profiler
Array (TIPA) based on an Offner Relay design has been
constructed as a THz beam profiler and multispectral imager.
It integrates a solid-state detector technology (Schottky
Diodes) that can be configured in an array to cover the
frequency range from 0.60 to 0.90 THz. The reconfigurable 16
element Schottky diode detector array is utilized along with
imaging and scanning mirror modules and system control
hardware and software to produce high spatial or temporal
beam profiles of THz beams. Images of THz source profiles
are presented along with THz images of relevant targets.
Potential applications are discussed. © 2010 Copyright SPIE
- The International Society for Optical Engineering.},
Doi = {10.1117/12.849932},
Key = {Heimbeck:2010cy}
}
@inproceedings{Phillips:kr,
Author = {Phillips, DJ and Tanner, EA and Everitt, HO and Medvedev, IR and Neese,
CF and Holt, J and De Lucia and FC},
Title = {Infrared/terahertz double resonance for chemical remote
sensing: Signatures and performance predictions},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7671},
Pages = {76710F--76710F--12},
Booktitle = {Terahertz Physics, Devices, and Systems IV: Advanced
Applications in Industry and Defense},
Publisher = {SPIE},
Year = {2010},
Month = {June},
ISBN = {9780819481351},
url = {http://link.aip.org/link/PSISDG/v7671/i1/p76710F/s1&Agg=doi},
Abstract = {Single resonance chemical remote sensing, such as
Fourier-transform infrared spectroscopy, has limited
recognition specificity because of atmospheric pressure
broadening. Active interrogation techniques promise much
greater chemical recognition that can overcome the limits
imposed by atmospheric pressure broadening. Here we
introduce infrared - terahertz (IR/THz) double resonance
spectroscopy as an active means of chemical remote sensing
that retains recognition specificity through rare,
molecule-unique coincidences between IR molecular absorption
and a line-tunable CO2 excitation laser. The laser-induced
double resonance is observed as a modulated THz spectrum
monitored by a THz transceiver. As an example, our analysis
indicates that a 1 ppm cloud of CH3F 100 m thick can be
detected at distances up to 1 km using this technique. ©
2010 Copyright SPIE - The International Society for Optical
Engineering.},
Doi = {10.1117/12.853309},
Key = {Phillips:kr}
}
@article{Smith:2010fl,
Author = {Smith, ER and Gruber, JB and Wellenius, P and Muth, JF and Everitt,
HO},
Title = {Spectra and energy levels of Eu3+ in cubic phase
Gd2O3},
Journal = {Physica Status Solidi (B) Basic Research},
Volume = {247},
Number = {7},
Pages = {1807-1813},
Publisher = {WILEY},
Organization = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Institution = {Duke Univ, Dept Phys, Durham, NC 27708 USA},
Year = {2010},
Month = {July},
url = {http://links.isiglobalnet2.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=mekentosj&SrcApp=Papers&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000280263700049},
Abstract = {In pulsed laser deposition of the sesquioxide semiconductor
Gd2O3, adjusting the chamber oxygen pressure controls the
crystalline structure of the host. This technique was used
to deposit thin films of nominally 1.6% by weight
europiumdoped, cubic phase Gd2O3 using 50 mTorr of oxygen.
Structural measurements using high-resolution transmission
electron microscopy and selected area electron diffraction
confirm the films were polycrystalline, cubic phase
Eu:Gd2O3. The spectroscopic assignment of emission lines to
specific radiative transitions within the trivalent Eu ion
is confirmed by theoretical analysis of the appropriate
crystal field Hamiltonian. Detailed crystal-field splittings
are presented for the 5DJ=0-2 and 7FJ=0-5 multiplet
manifolds of Eu3+ in this host material. © 2010 WILEY-VCH
Verlag GmbH & Co. KGaA, Weinheim.},
Language = {English},
Doi = {10.1002/pssb.200945602},
Key = {Smith:2010fl}
}
@article{Wellenius:2010eb,
Author = {Wellenius, P and Smith, ER and Wu, PC and Everitt, HO and Muth,
JF},
Title = {Effect of oxygen pressure on the structure and luminescence
of Eu-doped Gd 2O 3 thin
films},
Journal = {Physica Status Solidi (A)},
Volume = {207},
Number = {8},
Pages = {1949-1953},
Publisher = {WILEY},
Organization = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27606 USA},
Institution = {N Carolina State Univ, Dept Elect {\&} Comp Engn, Raleigh,
NC 27606 USA},
Year = {2010},
Month = {August},
ISSN = {1862-6300},
url = {http://links.isiglobalnet2.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=mekentosj&SrcApp=Papers&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000281691300030},
Abstract = {Europium-doped gadolinium oxide (Gd2O3) thin films were
deposited on sapphire substrates by pulsed laser deposition
(PLD). The effect of oxygen pressure during deposition on
the structure of the thin films, investigated by
transmission electron microscopy (TEM) and X-ray diffraction
(XRD), was correlated to photoluminescence spectra. The
polycrystalline films, like the one deposited in 5 mTorr
oxygen environment, were primarily monoclinic phase; however
the rarer cubic phase was achieved at 50 mTorr pressure.
Time-integrated and timeresolved photoluminescence (TIPL and
TRPL) spectra of the bright 5D 0 to 7F 2 radiative
transition revealed how the differing host material phases
altered the local environment of the Eu dopants. © 2010
WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
Language = {English},
Doi = {10.1002/pssa.201026071},
Key = {Wellenius:2010eb}
}
@article{2010OptL...35.3658H,
Author = {Heimbeck, MS and Reardon, PJ and Callahan, J and Everitt,
HO},
Title = {Transmissive quasi-optical Ronchi phase grating for
terahertz frequencies.},
Journal = {Optics Letters},
Volume = {35},
Number = {21},
Pages = {3658-3660},
Organization = {USA, Aviat {\&} Missile RD{\&}E Ctr, Weap Sci Directorate,
Redstone Arsenal, AL 35898 USA},
Institution = {USA, Aviat {\&} Missile RD{\&}E Ctr, Weap Sci Directorate,
Redstone Arsenal, AL 35898 USA},
Year = {2010},
Month = {November},
ISSN = {0146-9592},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010OptL...35.3658H&link_type=EJOURNAL},
Abstract = {A transmissive, square-wave Ronchi phase grating has been
fabricated from the dielectric polytetrafluoroethylene to
diffract an ~0.7 THz beam quasi-optically. When illuminated
by a coherent, cw terahertz (THz) source, the spot
separation of the ±1 diffractive orders and the diffraction
efficiency were measured as a function of THz frequency and
rotation angle. The grating performance depends sensitively
on the refractive index, whose value can be measured with an
accuracy limited by the fabrication precision. The use of
these gratings for polarization-insensitive quasi-optical
imaging and phased arrays is discussed.},
Language = {English},
Doi = {10.1364/ol.35.003658},
Key = {2010OptL...35.3658H}
}
@article{fds314097,
Author = {Everitt, H and Evans, SL and Holt, CA and Bigsby, R and Khan,
I},
Title = {Acetabular component deformation under rim loading using
Digital Image Correlation and finite element
methods},
Journal = {Applied Mechanics and Materials},
Volume = {24-25},
Pages = {275-280},
Publisher = {Trans Tech Publications},
Year = {2010},
Month = {December},
ISBN = {9780878492480},
url = {http://dx.doi.org/10.4028/www.scientific.net/AMM.24-25.275},
Abstract = {Total hip replacement is a highly successful operation;
restoring function and reducing pain in arthritis patients.
In recent years, thinner resurfacing acetabular cups have
been introduced in order to preserve bone stock and reduce
the risk of dislocation. However concerns have been raised
that deformation of these cups could adversely affect the
lubrication regime of the bearing; leading to equatorial and
edge contact, possibly causing the implants to jam. This
study aims to assess the amount of deformation which occurs
due to the tight peripheral fit experienced during press-fit
by applying rim loading to three different designs of
acetabular cup: a clinically successful cobalt chrome
resurfacing cup, a prototype composite resurfacing cup and a
clinically successful polyethylene monobloc cup. Digital
Image Correlation (DIC) was used to measure the deformation
and to validate Finite Element (FE) models. DIC provided a
non-contacting method to measure displacement; meaning the
load could be increased continuously rather than in steps as
in previous studies. The physical testing showed that the
cobalt chrome cups were significantly stiffer than the
composite prototype and polyethylene cups. The FE models
were in good agreement with the experimental results for all
three cups and were able to predict the deformation to
within 10%. FE models were also created to investigate the
effect of cup outside diameter and wall thickness on
stiffness under rim loading. Increasing outside diameter
resulted in a linear reduction in stiffness for all three
materials. Increasing the wall thickness resulted in an
exponential increase in cup stiffness. Rim loading an
acetabular shell does not accurately simulate the in vivo
conditions; however it does provide a simple method for
comparing cups made of different materials. © (2010) Trans
Tech Publications, Switzerland.},
Doi = {10.4028/www.scientific.net/AMM.24-25.275},
Key = {fds314097}
}
@article{2011OExpr..19.7513C,
Author = {Chua, S-L and Caccamise, CA and Phillips, DJ and Joannopoulos, JD and Soljacić, M and Everitt, HO and Bravo-Abad, J},
Title = {Spatio-temporal theory of lasing action in optically-pumped
rotationally excited molecular gases.},
Journal = {Optics Express},
Volume = {19},
Number = {8},
Pages = {7513-7529},
Organization = {MIT, Dept Elect Engn {\&} Comp Sci, Cambridge, MA 02139
USA},
Institution = {MIT, Dept Elect Engn {\&} Comp Sci, Cambridge, MA 02139
USA},
Year = {2011},
Month = {April},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011OExpr..19.7513C&link_type=EJOURNAL},
Abstract = {We investigate laser emission from optically-pumped
rotationally excited molecular gases confined in a metallic
cavity. To this end, we have developed a theoretical
framework able to accurately describe, both in the spatial
and temporal domains, the molecular collisional and
diffusion processes characterizing the operation of this
class of lasers. The effect on the main lasing features of
the spatial variation of the electric field intensity and
the ohmic losses associated to each cavity mode are also
included in our analysis. Our simulations show that, for the
exemplary case of methyl fluoride gas confined in a
cylindrical copper cavity, the region of maximum population
inversion is located near the cavity walls. Based on this
fact, our calculations show that the lowest lasing threshold
intensity corresponds to the cavity mode that, while
maximizing the spatial overlap between the corresponding
population inversion and electric-field intensity
distributions, simultaneously minimizes the absorption
losses occurring at the cavity walls. The dependence of the
lasing threshold intensity on both the gas pressure and the
cavity radius is also analyzed and compared with experiment.
We find that as the cavity size is varied, the interplay
between the overall gain of the system and the corresponding
ohmic losses allows for the existence of an optimal cavity
radius which minimizes the intensity threshold for a large
range of gas pressures. The theoretical analysis presented
in this work expands the current understanding of lasing
action in optically-pumped far-infrared lasers and, thus,
could contribute to the development of a new class of
compact far-infrared and terahertz sources able to operate
efficiently at room temperature.},
Language = {English},
Doi = {10.1364/oe.19.007513},
Key = {2011OExpr..19.7513C}
}
@article{Heimbeck:2011vb,
Author = {Heimbeck, MS and Kim, MK and Gregory, DA and Everitt,
HO},
Title = {Terahertz digital holography using angular spectrum and dual
wavelength reconstruction methods.},
Journal = {Optics Express},
Volume = {19},
Number = {10},
Pages = {9192-9200},
Year = {2011},
Month = {May},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011OExpr..19.9192H&link_type=EJOURNAL},
Abstract = {Terahertz digital off-axis holography is demonstrated using
a Mach-Zehnder interferometer with a highly coherent,
frequency tunable, continuous wave terahertz source emitting
around 0.7 THz and a single, spatially-scanned Schottky
diode detector. The reconstruction of amplitude and phase
objects is performed digitally using the angular spectrum
method in conjunction with Fourier space filtering to reduce
noise from the twin image and DC term. Phase unwrapping is
achieved using the dual wavelength method, which offers an
automated approach to overcome the 2π phase ambiguity.
Potential applications for nondestructive test and
evaluation of visually opaque dielectric and composite
objects are discussed.},
Doi = {10.1364/oe.19.009192},
Key = {Heimbeck:2011vb}
}
@inproceedings{Ruffin:2011ez,
Author = {Ruffin, PB and Brantley, CL and Edwards, E and Roberts, JK and Chew, W and Warren, LC and Ashley, PR and Everitt, HO and Webster, E and Foreman,
JV and Sanghadasa, M and Crutcher, SH and Temmen, MG and Varadan, V and Hayduke, D and Wu, PC and Khoury, CG and Yang, Y and Kim, TH and Vo-Dinh,
T and Brown, AS and Callahan, J},
Title = {Nanotechnology research and development for military and
industrial applications},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7980},
Pages = {798002--798002--17},
Booktitle = {Nanosensors, Biosensors, and Info-Tech Sensors and Systems
2011},
Publisher = {SPIE},
Year = {2011},
Month = {May},
ISSN = {0277-786X},
url = {http://link.aip.org/link/PSISDG/v7980/i1/p798002/s1&Agg=doi},
Abstract = {Researchers at the Army Aviation and Missile Research,
Development, and Engineering Center (AMRDEC) have initiated
multidiscipline efforts to develop nano-based structures and
components for insertion into advanced missile, aviation,
and autonomous air and ground systems. The objective of the
research is to exploit unique phenomena for the development
of novel technology to enhance warfighter capabilities and
produce precision weapons. The key technology areas that the
authors are exploring include nano-based microsensors,
nano-energetics, nano-batteries, nano-composites, and
nano-plasmonics. By integrating nano-based devices,
structures, and materials into weaponry, the Army can
revolutionize existing (and future) missile systems by
significantly reducing the size, weight and cost. The major
research thrust areas include the development of chemical
sensors to detect rocket motor off-gassing and toxic
industrial chemicals; the development of highly
sensitive/selective, self-powered miniaturized acoustic
sensors for battlefield surveillance and reconnaissance; the
development of a minimum signature solid propellant with
increased ballistic and physical properties that meet
insensitive munitions requirements; the development of
nano-structured material for higher voltage thermal
batteries and higher energy density storage; the development
of advanced composite materials that provide high frequency
damping for inertial measurement units' packaging; and the
development of metallic nanostructures for ultraviolet
surface enhanced Raman spectroscopy. The current status of
the overall AMRDEC Nanotechnology research efforts is
disclosed in this paper. Critical technical challenges, for
the various technologies, are presented. The authors'
approach for overcoming technical barriers and achieving
required performance is also discussed. Finally, the roadmap
for each technology, as well as the overall program, is
presented. © 2011 Copyright Society of Photo-Optical
Instrumentation Engineers (SPIE).},
Language = {English},
Doi = {10.1117/12.878970},
Key = {Ruffin:2011ez}
}
@article{Albella:2011br,
Author = {Albella, P and Garcia-Cueto, B and González, F and Moreno, F and Wu,
PC and Kim, T-H and Brown, A and Yang, Y and Everitt, HO and Videen,
G},
Title = {Shape matters: plasmonic nanoparticle shape enhances
interaction with dielectric substrate.},
Journal = {Nano Letters},
Volume = {11},
Number = {9},
Pages = {3531-3537},
Publisher = {American Chemical Society},
Year = {2011},
Month = {September},
ISSN = {1530-6984},
url = {http://pubs.acs.org/doi/abs/10.1021/nl201783v},
Abstract = {Numerical analyses of the ultraviolet and visible plasmonic
spectra measured from hemispherical gallium nanostructures
on dielectric substrates reveal that resonance frequencies
are quite sensitive to illumination angle and polarization
in a way that depends on nanostructure size, shape, and
substrate. Large, polarization-dependent splittings arise
from the broken symmetry of hemispherical gallium
nanoparticles on sapphire substrates, inducing strong
interactions with the substrate that depend sensitively on
the angle of illumination and the nanoparticle
diameter.},
Language = {English},
Doi = {10.1021/nl201783v},
Key = {Albella:2011br}
}
@article{fds314075,
Author = {Heimbeck, MS and Wilson, DG and Frees, AE and Everitt,
HO},
Title = {Continuous wave terahertz transmission imaging through
near-field aperture funnels},
Journal = {Irmmw Thz 2011 36th International Conference on Infrared,
Millimeter, and Terahertz Waves},
Publisher = {IEEE},
Year = {2011},
Month = {December},
ISBN = {9781457705090},
ISSN = {2162-2027},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000330296300233&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We report high throughput, continuous wave terahertz imaging
using a near-field funnel aperture with adjustable output
diameter. The frequency dependence of the output power and
resolution immediately following the aperture are reported,
as are the propagation and resolution characteristics as a
function of distance from the aperture. © 2011
IEEE.},
Doi = {10.1109/irmmw-THz.2011.6104988},
Key = {fds314075}
}
@article{fds314085,
Author = {Heimbeck, MS and Kim, MK and Gregory, DA and Everitt,
HO},
Title = {Terahertz digital off-axis holography for non-destructive
testing},
Journal = {Irmmw Thz 2011 36th International Conference on Infrared,
Millimeter, and Terahertz Waves},
Publisher = {IEEE},
Year = {2011},
Month = {December},
ISBN = {9781457705090},
ISSN = {2162-2027},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000330296300335&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Terahertz digital off-axis holography is demonstrated with a
highly coherent, frequency tunable continuous wave terahertz
source emitting between 0.1 and 0.8 THz and a single
spatially-scanned Schottky diode detector. The angular
spectrum and dual wavelength reconstruction methods are
employed for the digital reconstruction process. © 2011
IEEE.},
Doi = {10.1109/irmmw-THz.2011.6105090},
Key = {fds314085}
}
@article{fds314088,
Author = {Phillips, DJ and Tanner, EA and Everitt, HO and De Lucia,
FC},
Title = {Infrared/terahertz double resonance spectroscopy remote
sensing},
Journal = {Irmmw Thz 2011 36th International Conference on Infrared,
Millimeter, and Terahertz Waves},
Publisher = {IEEE},
Year = {2011},
Month = {December},
ISBN = {9781457705090},
ISSN = {2162-2027},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000330296300360&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {IR/THz double resonance spectroscopy has recently been
proposed as a method of chemical remote sensing with
isotopic molecular recognition specificity at atmospheric
pressures for distances approaching one kilometer. Double
resonance signatures are calculated, from which the
sensitivity and hardware requirements for a double resonance
remote sensing spectrometer may be estimated. The extension
of this technique to heavier and more complex molecules is
discussed. © 2011 IEEE.},
Doi = {10.1109/irmmw-THz.2011.6105115},
Key = {fds314088}
}
@article{fds314059,
Author = {Heimbeck, MS and Reardon, PJ and Goldberg, J and Einhorn, M and Everitt,
HO},
Title = {Multi detector terahertz beam profiling and imaging
instrument},
Journal = {Irmmw Thz 2011 36th International Conference on Infrared,
Millimeter, and Terahertz Waves},
Publisher = {IEEE},
Year = {2011},
Month = {December},
ISBN = {9781457705090},
ISSN = {2162-2027},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000330296300427&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {A reconfigurable, all-reflective terahertz imager has been
constructed, capable of 4096-pixel resolution in 20 seconds.
The imager spans 0.09-0.90 THz in 5 bands, each represented
by a 16-element detector array. Both, beam profiling and
confocal imaging configurations have been demonstrated. ©
2011 IEEE.},
Doi = {10.1109/irmmw-THz.2011.6105182},
Key = {fds314059}
}
@article{Cho:2011ef,
Author = {Cho, J and Lin, Q and Yang, S and Jr, JGS and Cheng, Y and Lin, E and Yang, J and Foreman, JV and Everitt, HO and Yang, W and Kim, J and Liu,
J},
Title = {Sulfur-doped zinc oxide (ZnO) Nanostars: Synthesis and
simulation of growth mechanism},
Journal = {Nano Research},
Volume = {5},
Number = {1},
Pages = {20-26},
Publisher = {Springer Nature},
Year = {2012},
ISSN = {1998-0124},
url = {http://www.springerlink.com/index/10.1007/s12274-011-0180-3},
Abstract = {We present a bottom-up synthesis, spectroscopic
characterization, and ab initio simulations of star-shaped
hexagonal zinc oxide (ZnO) nanowires. The ZnO nanostructures
were synthesized by a low-temperature hydrothermal growth
method. The cross-section of the ZnO nanowires transformed
from a hexagon to a hexagram when sulfur dopants from
thiourea [SC(NH 2) 2] were added into the growth solution,
but no transformation occurred when urea (OC(NH 2) 2) was
added. Comparison of the X-ray photoemission and
photoluminescence spectra of undoped and sulfur-doped ZnO
confirmed that sulfur is responsible for the novel
morphology. Large-scale theoretical calculations were
conducted to understand the role of sulfur doping in the
growth process. The ab initio simulations demonstrated that
the addition of sulfur causes a local change in charge
distribution that is stronger at the vertices than at the
edges, leading to the observed transformation from hexagon
to hexagram nanostructures. © 2012 Tsinghua University
Press and Springer-Verlag Berlin Heidelberg.},
Language = {English},
Doi = {10.1007/s12274-011-0180-3},
Key = {Cho:2011ef}
}
@article{fds372054,
Author = {Tonkin-Crine, S and Bishop, F and Ellis, M and Moss-Morris, R and Everitt, H},
Title = {Exploring patients' views of a self-management CBT-based
website for the management of IBS},
Journal = {Psychology & Health},
Volume = {27},
Pages = {130-130},
Year = {2012},
Key = {fds372054}
}
@article{2012OExpr..20.1868M,
Author = {Mattiucci, N and D'Aguanno, G and Everitt, HO and Foreman, JV and Callahan, JM and Buncick, MC and Bloemer, MJ},
Title = {Ultraviolet surface-enhanced Raman scattering at the
plasmonic band edge of a metallic grating.},
Journal = {Optics Express},
Volume = {20},
Number = {2},
Pages = {1868-1877},
Organization = {AEgis Tech, Nanogenesis Div, Huntsville, AL 35806
USA},
Institution = {AEgis Tech, Nanogenesis Div, Huntsville, AL 35806
USA},
Year = {2012},
Month = {January},
url = {http://www.nanogenesisgroup.com/PDFs/Journal},
Abstract = {Surface-enhanced Raman Scattering (SERS) is studied in
sub-wavelength metallic gratings on a substrate using a
rigorous electromagnetic approach. In the ultraviolet SERS
is limited by the metallic dampening, yet enhancements as
large as 10(5) are predicted. It is shown that these
enhancements are directly linked to the spectral position of
the plasmonic band edge of the metal/substrate surface
plasmon. A simple methodology is presented for selecting the
grating pitch to produce optimal enhancement for a given
laser frequency.},
Language = {English},
Doi = {10.1364/oe.20.001868},
Key = {2012OExpr..20.1868M}
}
@article{fds349747,
Author = {D'Aguanno, G and Mattiucci, N and Butun, S and Callahan, JM and Everitt,
HO and Aydin, K and Bloemer, MJ},
Title = {UV-SERS assisted by nano-focusing in plasmonic gratings with
tapered slits},
Journal = {Frontiers in Optics, Fio 2012},
Year = {2012},
Month = {January},
ISBN = {9781557529565},
url = {http://dx.doi.org/10.1364/fio.2012.ftu3a.68},
Abstract = {The potential for UV-SERS is demonstrated using
subwavelength Al gratings grown on sapphire substrate. The
role played by the slit geometry and analyte coverage is
explored, demonstrating that enhancement factors greater
than 100,000 are possible. © OSA 2012.},
Doi = {10.1364/fio.2012.ftu3a.68},
Key = {fds349747}
}
@article{fds351268,
Author = {Everitt, H},
Title = {Coherent terahertz holographic and tomographic
imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2012},
Month = {January},
ISBN = {1557529477},
url = {http://dx.doi.org/10.1364/sensors.2012.sw3c.5},
Abstract = {This talk will survey the application of digital holographic
and tomographic techniques to highly coherent, single
frequency terahertz sources and extremely sensitive
heterodyne receivers for high resolution three dimensional
reconstructions of extended, visibly opaque objects. © 2012
OSA.},
Doi = {10.1364/sensors.2012.sw3c.5},
Key = {fds351268}
}
@article{2012arXiv1202.0595P,
Author = {Phillips, Dane J and Tanner, Elizabeth A and de Lucia, Frank
C and Everitt, Henry O},
Title = {Infrared/Terahertz double resonance spectroscopy of CH3F and
CH3Cl at atmospheric pressure},
Journal = {arXiv.org},
Pages = {595},
Year = {2012},
Month = {February},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012arXiv1202.0595P&link_type=ABSTRACT},
Abstract = {A new method for highly selective remote sensing of
atmospheric trace polar molecular gases is described. Based
on infrared/terahertz double resonance spectroscopic
techniques, the molecule- specific coincidence between the
lines of a CO2 laser and rotational-vibrational molecular
absorption transitions provide two dimensions of recognition
specificity: infrared coincidence frequency and the
corresponding terahertz frequency whose absorption strength
is modulated by the laser. Atmospheric pressure broadening
expands the molecular recognition "specificity matrix" by
simultaneously relaxing the infrared coincidence requirement
and strengthening the corresponding terahertz signature.
Representative double resonance spectra are calculated for
prototypical molecules CH3F and CH3Cl and their principal
isotopomers, from which a heuristic model is developed to
estimate the specificity matrix and double resonance
signature strength for any polar molecule.},
Key = {2012arXiv1202.0595P}
}
@article{fds314131,
Author = {Halbur, J and Krommenhoek, PJ and Everitt, HO and Tracy, JB and Jur,
JS},
Title = {Enabling of nanoparticle application and function on the
surface of fibrous textiles by atomic layer
deposition},
Journal = {Abstracts of Papers of the American Chemical
Society},
Volume = {243},
Pages = {1 pages},
Publisher = {AMER CHEMICAL SOC},
Year = {2012},
Month = {March},
ISSN = {0065-7727},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000324475104033&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Key = {fds314131}
}
@article{Heimbeck:2012ka,
Author = {Heimbeck, MS and Marks, DL and Brady, D and Everitt,
HO},
Title = {Terahertz interferometric synthetic aperture tomography for
confocal imaging systems.},
Journal = {Optics Letters},
Volume = {37},
Number = {8},
Pages = {1316-1318},
Year = {2012},
Month = {April},
ISSN = {0146-9592},
url = {http://www.opticsinfobase.org/abstract.cfm?URI=ol-37-8-1316},
Abstract = {Terahertz (THz) interferometric synthetic aperture
tomography (TISAT) for confocal imaging within extended
objects is demonstrated by combining attributes of synthetic
aperture radar and optical coherence tomography. Algorithms
recently devised for interferometric synthetic aperture
microscopy are adapted to account for the diffraction-and
defocusing-induced spatially varying THz beam width
characteristic of narrow depth of focus, high-resolution
confocal imaging. A frequency-swept two-dimensional TISAT
confocal imaging instrument rapidly achieves in-focus,
diffraction-limited resolution over a depth 12 times larger
than the instrument's depth of focus in a manner that may be
easily extended to three dimensions and greater
depths.},
Language = {English},
Doi = {10.1364/ol.37.001316},
Key = {Heimbeck:2012ka}
}
@article{2012PhRvA..85e2507P,
Author = {Phillips, DJ and Tanner, EA and De Lucia and FC and Everitt,
HO},
Title = {Infrared-terahertz double-resonance spectroscopy of CH
3F and CH 3Cl at atmospheric
pressure},
Journal = {Physical Review A},
Volume = {85},
Number = {5},
Pages = {52507--},
Publisher = {American Physical Society (APS)},
Organization = {Kratos--Digital Fusion, 4904 Research Drive, Huntsville,
Alabama 35805, USA},
Institution = {Kratos--Digital Fusion, 4904 Research Drive, Huntsville,
Alabama 35805, USA},
Year = {2012},
Month = {May},
ISSN = {1050-2947},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012PhRvA..85e2507P&link_type=ABSTRACT},
Abstract = {A method for highly selective remote sensing of atmospheric
trace polar molecular gases is described. Based on
infrared-terahertz double-resonance spectroscopic
techniques, the molecule-specific coincidence between the
lines of a CO 2 laser and rotational-vibrational molecular
absorption transitions provide two dimensions of recognition
specificity: infrared coincidence frequency and the
corresponding terahertz frequency whose absorption strength
is modulated by the laser. Atmospheric pressure broadening
expands the molecular recognition "specificity matrix" by
simultaneously relaxing the infrared coincidence requirement
and strengthening the corresponding terahertz signature.
Representative double-resonance spectra are calculated for
prototypical molecules CH 3F and CH 3Cl and their principal
isotopomers from which a heuristic model is developed to
estimate the specificity matrix and double-resonance
signature strength for any polar molecule. © 2012 American
Physical Society.},
Language = {English},
Doi = {10.1103/PhysRevA.85.052507},
Key = {2012PhRvA..85e2507P}
}
@article{fds314063,
Author = {Kumar, S},
Title = {Operation of terahertz quantum cascade lasers above 160 K
covering a frequency range of 2-4 THz},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8496},
Publisher = {SPIE},
Editor = {Razeghi, M and Baranov, AN and Everitt, HO and Zavada, JM and Manzur,
T},
Year = {2012},
Month = {October},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312110600001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Doi = {10.1117/12.929760},
Key = {fds314063}
}
@article{Knight:2012ta,
Author = {Knight, MW and Liu, L and Wang, Y and Brown, L and Mukherjee, S and King,
NS and Everitt, HO and Nordlander, P and Halas, NJ},
Title = {Aluminum plasmonic nanoantennas.},
Journal = {Nano Letters},
Volume = {12},
Number = {11},
Pages = {6000-6004},
Organization = {Rice University, Houston, TX},
Institution = {Rice University, Houston, TX},
Year = {2012},
Month = {November},
url = {http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012NanoL..12.6000K&link_type=EJOURNAL},
Abstract = {The use of aluminum for plasmonic nanostructures opens up
new possibilities, such as access to short-wavelength
regions of the spectrum, complementary metal-oxide-semiconductor
(CMOS) compatibility, and the possibility of low-cost,
sustainable, mass-producible plasmonic materials. Here we
examine the properties of individual Al nanorod antennas
with cathodoluminescence (CL). This approach allows us to
image the local density of optical states (LDOS) of Al
nanorod antennas with a spatial resolution less than 20 nm
and to identify the radiative modes of these nanostructures
across the visible and into the UV spectral range. The
results, which agree well with finite difference time domain
(FDTD) simulations, lay the groundwork for precise Al
plasmonic nanostructure design for a variety of
applications.},
Doi = {10.1021/nl303517v},
Key = {Knight:2012ta}
}
@article{fds314092,
Author = {Butler, L and Wilbert, DS and Baughman, W and Balci, S and Kung, P and Kim,
SM and Heimbeck, MS and Everitt, HO},
Title = {Design, simulation, and characterization of THz metamaterial
absorber},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8363},
Publisher = {SPIE},
Year = {2012},
Month = {December},
ISBN = {9780819490414},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000305795500011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In recent years a great amount of research has been focused
on metamaterials, initially for fabrication of left-handed
materials for use in devices such as superlenses or
electromagnetic cloaking. Such devices have been developed
and demonstrated in regimes from the radio frequency all the
way to infrared and near optical frequencies. More recently,
it has been shown that, by careful adjustment of the
effective permittivity and permeability, near perfect
electromagnetic absorbers can be realized. High absorption
occurs when transmission and reflection are simultaneously
minimized. With some clever tuning of the electric and
magnetic responses, the electric and magnetic energy can
therefore both be absorbed by the same metamaterial
structure. In this work we present the design, simulation
and characterization of a novel thin, flexible, polarization
insensitive metamaterial absorber. Finite-element simulation
results show that this device achieves almost perfect
absorption at THz frequencies. Each unit cell of the
absorber is made up of two metallic structures separated by
a dielectric filler material. The electric response can be
tuned by adjusting the geometry of the top metallic electric
ring resonator structure. We demonstrate that a rotation
about the axis of THz wave propagation at normal incidence
does not change the absorption or the resonance frequency by
a significant amount. A value of absorption of 99.6 % at a
resonance frequency of 0.84 THz can be achieved. We also
demonstrate the characteristics of this absorber structure
under various THz wave incidence angles, with respect to
both the incident electric and magnetic fields. © 2012
SPIE.},
Doi = {10.1117/12.919625},
Key = {fds314092}
}
@inproceedings{Baughman:2012hm,
Author = {Baughman, WE and Wilbert, DS and Balci, S and Bolus, M and Baker, M and Kung, P and Kim, SM and Heimbeck, MS and Everitt,
HO},
Title = {Comparative reconstructions of THz spectroscopic imaging for
non-destructive testing and biomedical imaging},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8363},
Pages = {83630W--83630W--10},
Booktitle = {Terahertz Physics, Devices, and Systems VI: Advanced
Applications in Industry and Defense},
Publisher = {SPIE},
Year = {2012},
Month = {December},
ISBN = {9780819490414},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000305795500021&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Imaging with electromagnetic radiation in the THz frequency
regime, between 0.2 THz and 10 THz, has made considerable
progress in recent years due to the unique properties of THz
radiation, such as being non-ionizing and transparent
through many materials. This makes THz imaging and sensing
promising for a plethora of applications; most notably for
contraband detection and biomedical diagnostics. Though many
methods of generation and detection terahertz radiation
exist, in this study we utilize Terahertz Time Domain
Spectroscopy (THz TDS) and THz digital holography using a
coherent, tunable CW THz source. These methods enable access
to both the amplitude and phase information of the traveling
THz waves. As a result of the direct time-resolved detection
method of the THz electric field, unique spectroscopic
information about the objects traversed can be extracted
from the measurements in addition to being able to yield
intensity imaging contrast. Utilizing such capabilities for
THz based imaging can be useful for both screening and
diagnostic applications. In this work, we present the
principles and applications of several reconstruction
algorithms applied to THz imaging and sensing. We
demonstrate its ability to achieve multi-dimensional imaging
contrast of both soft tissues and concealed objects. © 2012
SPIE.},
Doi = {10.1117/12.919627},
Key = {Baughman:2012hm}
}
@article{fds331987,
Author = {Everitt, H},
Title = {Coherent terahertz holographic and tomographic
imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2012},
Month = {December},
ISBN = {1557529477},
Abstract = {This talk will survey the application of digital holographic
and tomographic techniques to highly coherent, single
frequency terahertz sources and extremely sensitive
heterodyne receivers for high resolution three dimensional
reconstructions of extended, visibly opaque objects. © 2012
OSA.},
Key = {fds331987}
}
@article{fds331988,
Author = {D'Aguanno, G and Mattiucci, N and Butun, S and Callahan, JM and Everitt,
HO and Aydin, K and Bloemer, MJ},
Title = {UV-SERS assisted by nano-focusing in plasmonic gratings with
tapered slits},
Journal = {Frontiers in Optics, Fio 2012},
Year = {2012},
Month = {December},
ISBN = {9781557529565},
Abstract = {The potential for UV-SERS is demonstrated using
subwavelength Al gratings grown on sapphire substrate. The
role played by the slit geometry and analyte coverage is
explored, demonstrating that enhancement factors greater
than 100,000 are possible. © OSA 2012.},
Key = {fds331988}
}
@article{fds331989,
Author = {Heimbeck, MS and Everitt, HO},
Title = {Polarization sensitive terahertz digital
holography},
Journal = {Frontiers in Optics, Fio 2012},
Year = {2012},
Month = {December},
ISBN = {9781557529565},
Abstract = {We report on a Terahertz imaging methodology that combines
digital holography and polarimetry to characterize objects
in transmission and reflection geometries on their
geometrical and physical properties in the Terahertz region
between 0.3 - 1.0 THz. Digital reconstruction methods are
implemented to extract both amplitude and phase images of
objects. The plane wave back propagation algorithms allow
the polarization information of object-beam interactions to
be extracted from the holograms. © OSA 2012.},
Key = {fds331989}
}
@article{Yang:2013vx,
Author = {Yang, Y and Callahan, J M and Kim, T H and Brown, A S and Everitt, H O},
Title = {Ultraviolet nano-plasmonics: A demonstration of
surface-enhanced Raman spectroscopy, fluorescence, and
photo-degradation using gallium nanoparticles},
Journal = {Nano Letters},
Volume = {13},
Number = {6},
Pages = {2837--2841},
Year = {2013},
url = {http://pubs.acs.org/doi/abs/10.1021/nl401145j},
Abstract = {Self-assembled arrays of hemispherical gallium nanoparticles
deposited by molecular beam epitaxy on a sapphire support
are explored as a new type of substrate for ultraviolet
plasmonics . Spin casting a 5 nm film of crystal violet upon
these nanoparticles permitted ...},
Key = {Yang:2013vx}
}
@article{fds331986,
Author = {Mrozack, A and Heimbeck, M and Marks, DL and Richard, J and Everitt, HO and Brady, DJ},
Title = {Adaptive scanning for synthetic aperture
imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {Synthetic aperture imagers measure the space-bandwidth
product of full-apertures by moving a single detector. We
show results from an adaptive sensing experiment that
demonstrate a three times speedup over full-scans. © 2013
Optical Society of America.},
Key = {fds331986}
}
@article{fds349919,
Author = {Mrozack, A and Heimbeck, M and Marks, DL and Richard, J and Everitt, HO and Brady, DJ},
Title = {Adaptive scanning for synthetic aperture
imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529879},
url = {http://dx.doi.org/10.1364/fio.2013.fm4i.4},
Abstract = {Synthetic aperture imagers measure the space-bandwidth
product of full-apertures by moving a single detector. We
show results from an adaptive sensing experiment that
demonstrate a three times speedup over full-scans. © 2013
Optical Society of America.},
Doi = {10.1364/fio.2013.fm4i.4},
Key = {fds349919}
}
@article{Foreman:2013ij,
Author = {Foreman, JV and Simmons, JG and Baughman, WE and Liu, J and Everitt,
HO},
Title = {Localized excitons mediate defect emission in ZnO
powders},
Journal = {Journal of Applied Physics},
Volume = {113},
Number = {13},
Pages = {133513-133513},
Publisher = {AIP Publishing},
Year = {2013},
Month = {April},
ISSN = {0021-8979},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000317238000019&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {A series of continuous-wave spectroscopic measurements
elucidates the mechanism responsible for the technologically
important green emission from deep-level traps in ZnO:Zn
powders. Analysis of low-temperature photoluminescence (PL)
and PL excitation spectra for bound excitons compared to the
temperature-dependent behavior of the green emission reveals
a deep correlation between green PL and specific donor-bound
excitons. Direct excitation of these bound excitons produces
highly efficient green emission from near-surface defects.
When normalized by the measured external quantum efficiency,
the integrated PL for both excitonic and green emission
features grows identically with excitation intensity,
confirming the strong connection between green emission and
excitons. The implications of these findings are used to
circumscribe operational characteristics of doped ZnO-based
white light phosphors whose quantum efficiency is almost
twice as large when the bound excitons are directly excited.
© 2013 American Institute of Physics.},
Language = {English},
Doi = {10.1063/1.4798359},
Key = {Foreman:2013ij}
}
@article{Reynolds:2013jv,
Author = {Reynolds, JG and Reynolds, CL and Mohanta, A and Muth, JF and Rowe, JE and Everitt, HO and Aspnes, DE},
Title = {Shallow acceptor complexes in p-type ZnO},
Journal = {Applied Physics Letters},
Volume = {102},
Number = {15},
Pages = {152114-152114},
Publisher = {AIP Publishing},
Year = {2013},
Month = {April},
ISSN = {0003-6951},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000318269200045&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We show that N-doped ZnO films grown on sapphire can exhibit
significant (∼1018 cm-3) room-temperature p-type behavior
when sufficient nitrogen (N) is incorporated and the
material is annealed appropriately. Substitutional N on the
oxygen (O) sublattice is a deep acceptor; however, shallow
acceptor complexes involve N, H, and zinc vacancies (V Zn).
Combining secondary ion mass spectrometry, Raman-scattering,
photoluminescence, and Hall-effect data, we establish the
evolution of N from its initial incorporation on a Zn site
to a final shallow acceptor complex VZn-NO-H with an
ionization energy of ca. 130 meV. This complex is
responsible for the observed p-type behavior. © 2013 AIP
Publishing LLC.},
Language = {English},
Doi = {10.1063/1.4802753},
Key = {Reynolds:2013jv}
}
@article{2013NanoL..13.2837Y,
Author = {Yang, Y and Callahan, JM and Kim, T-H and Brown, AS and Everitt,
HO},
Title = {Ultraviolet nanoplasmonics: a demonstration of
surface-enhanced Raman spectroscopy, fluorescence, and
photodegradation using gallium nanoparticles.},
Journal = {Nano Letters},
Volume = {13},
Number = {6},
Pages = {2837-2841},
Year = {2013},
Month = {June},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23659187},
Abstract = {Self-assembled arrays of hemispherical gallium nanoparticles
deposited by molecular beam epitaxy on a sapphire support
are explored as a new type of substrate for ultraviolet
plasmonics. Spin-casting a 5 nm film of crystal violet upon
these nanoparticles permitted the demonstration of
surface-enhanced Raman spectra, fluorescence, and
degradation following excitation by a HeCd laser operating
at 325 nm. Measured local Raman enhancement factors
exceeding 10(7) demonstrate the potential of gallium
nanoparticle arrays for plasmonically enhanced ultraviolet
detection and remediation.},
Doi = {10.1021/nl401145j},
Key = {2013NanoL..13.2837Y}
}
@article{Mani:2013kk,
Author = {Mani, RG and Ramanayaka, AN and Ye, T and Heimbeck, MS and Everitt, HO and Wegscheider, W},
Title = {Terahertz photovoltaic detection of cyclotron resonance in
the regime of radiation-induced magnetoresistance
oscillations},
Journal = {Physical Review B},
Volume = {87},
Number = {24},
Pages = {245308},
Year = {2013},
Month = {June},
ISSN = {1098-0121},
url = {http://link.aps.org/doi/10.1103/PhysRevB.87.245308},
Abstract = {We examine and compare the diagonal magnetoresistance, Rxx,
and the photovoltage induced by microwave (42≤f<300 GHz)
and terahertz (f≥300 GHz) photoexcitation in the high
mobility quasi-two-dimensional GaAs/AlGaAs system. The data
demonstrate strong radiation-induced magnetoresistance
oscillations in Rxx to 360 GHz. In addition, cyclotron
resonance is observed in the photovoltage to 725 GHz. These
results show that our high-mobility GaAs/AlGaAs
two-dimensional electron system (2DES) specimens remain
photoactive in magnetotransport into the terahertz band. ©
2013 American Physical Society.},
Language = {English},
Doi = {10.1103/PhysRevB.87.245308},
Key = {Mani:2013kk}
}
@article{Sanz:2013uj,
Author = {Sanz, J M and Ortiz, D and de la Osa, R Alcaraz and Saiz, J
M and Gonz{\'a}lez, F and Brown, April S and Losurdo, Maria and Everitt, Henry O and Moreno, Fernando},
Title = {UV Plasmonic Behavior of Various Metal Nanoparticles in the
Near-and Far-Field Regimes: Geometry and Substrate
Effects},
Journal = {The Journal of Physical Chemistry C},
Volume = {117},
Pages = {19606--19615},
Year = {2013},
Month = {August},
url = {http://pubs.acs.org/doi/abs/10.1021/jp405773p},
Abstract = {The practical efficacy of technologically promising metals
for use in ultraviolet plasmonics (3- 6 eV) is assessed by
an exhaustive numerical analysis. This begins with estimates
of the near- field and far - field electromagnetic
enhancement factors of isolated hemispherical
...},
Key = {Sanz:2013uj}
}
@article{fds314121,
Author = {Sanz, JM and Ortiz, D and Alcaraz De La Osa and R and Saiz, JM and González, F and Brown, AS and Losurdo, M and Everitt, HO and Moreno,
F},
Title = {UV plasmonic behavior of various metal nanoparticles in the
near- and far-field regimes: Geometry and substrate
effects},
Journal = {The Journal of Physical Chemistry C},
Volume = {117},
Number = {38},
Pages = {19606-19615},
Publisher = {American Chemical Society (ACS)},
Year = {2013},
Month = {September},
ISSN = {1932-7447},
url = {http://dx.doi.org/10.1021/jp405773p},
Abstract = {The practical efficacy of technologically promising metals
for use in ultraviolet plasmonics (3-6 eV) is assessed by an
exhaustive numerical analysis. This begins with estimates of
the near- and far-field electromagnetic enhancement factors
of isolated hemispherical and spherical metallic
nanoparticles deposited on typical dielectric substrates
like sapphire, from which the potential of each metal for
plasmonic applications may be ascertained. The ultraviolet
plasmonic behavior of aluminum, chromium, copper, gallium,
indium, magnesium, palladium, platinum, rhodium, ruthenium,
titanium, and tungsten was compared with the well-known
behavior of gold and silver in the visible. After exploring
this behavior for each metal as a function of nanoparticle
shape and size, the deleterious effect caused by the metal's
native oxide is considered, and the potential for
applications such as surface-enhanced Raman spectroscopy,
accelerated photodegradation and photocatalysis is
addressed. © 2013 American Chemical Society.},
Doi = {10.1021/jp405773p},
Key = {fds314121}
}
@article{Roberts:2013cc,
Author = {Roberts, AT and Mohanta, A and Everitt, HO and Leach, JH and Van Den
Broeck and D and Hosalli, AM and Paskova, T and Bedair,
SM},
Title = {Spectroscopic investigation of coupling among asymmetric
InGaN/GaN multiple quantum wells grown on non-polar a-plane
GaN substrates},
Journal = {Applied Physics Letters},
Volume = {103},
Number = {18},
Pages = {181106-181106},
Publisher = {AIP Publishing},
Year = {2013},
Month = {October},
url = {http://link.aip.org/link/APPLAB/v103/i18/p181106/s1&Agg=doi},
Abstract = {Low defect density asymmetric multiple quantum wells (MQWs)
of InGaN/GaN grown on non-polar a-plane GaN substrates were
investigated using time-integrated and time-resolved
photoluminescence spectroscopy. Comparison of these spectra
with the predicted emission energies reveals that these QWs
may be spectrally resolved at low temperatures. However, a
combination of thermal activation and resonant tunneling of
carriers increasingly coupled the QWs, favoring emission
from the lowest energy QWs with increasing temperature in a
manner analogous to MQWs composed of other non-polar
semiconductor materials but unlike most InGaN MQWs grown on
polar substrates and influenced by the strong
polarization-dependent effects. © 2013 AIP Publishing
LLC.},
Language = {English},
Doi = {10.1063/1.4827536},
Key = {Roberts:2013cc}
}
@article{Knight:2013jg,
Author = {Knight, Mark W and King, Nicholas S and Liu, Lifei and Everitt, Henry O and Nordlander, Peter and Halas, Naomi
J},
Title = {Aluminum for Plasmonics},
Journal = {ACS Nano},
Volume = {8},
Number = {1},
Pages = {834--840},
Year = {2013},
Month = {November},
url = {http://pubs.acs.org/doi/abs/10.1021/nn405495q},
Abstract = {Unlike silver and gold, aluminum has material properties
that enable strong plasmon resonances spanning much of the
visible region of the spectrum and into the ultraviolet.
This extended response, combined with its natural abundance,
low cost, and amenability to manufacturing processes, makes
aluminum a highly promising material for commercial
applications. Fabricating Al-based nanostructures whose
optical properties correspond with theoretical predictions,
however, can be a challenge. In this work, the Al plasmon
resonance is observed to be remarkably sensitive to the
presence of oxide within the metal. For Al nanodisks, we
observe that the energy of the plasmon resonance is
determined by, and serves as an optical reporter of, the
percentage of oxide present within the Al. This
understanding paves the way toward the use of aluminum as a
low-cost plasmonic material with properties and potential
applications similar to those of the coinage
metals.},
Doi = {10.1021/nn405495q},
Key = {Knight:2013jg}
}
@article{Simmons:2013eg,
Author = {Simmons, JG and Foreman, JV and Liu, J and Everitt,
HO},
Title = {The dependence of ZnO photoluminescence efficiency on
excitation conditions and defect densities},
Journal = {Applied Physics Letters},
Volume = {103},
Number = {20},
Pages = {201110-201110},
Publisher = {AIP Publishing},
Year = {2013},
Month = {November},
url = {http://link.aip.org/link/APPLAB/v103/i20/p201110/s1&Agg=doi},
Abstract = {The quantum efficiencies of both the band edge and
deep-level defect emission from annealed ZnO powders were
measured as a function of excitation fluence and wavelength
from a tunable sub-picosecond source. A simple model of
excitonic decay reproduces the observed excitation
dependence of rate constants and associated trap densities
for all radiative and nonradiative processes. The analysis
explores how phosphor performance deteriorates as excitation
fluence and energy increase, provides an all-optical
approach for estimating the number density of defects
responsible for deep-level emission, and yields new insights
for designing efficient ZnO-based phosphors. © 2013 AIP
Publishing LLC.},
Language = {English},
Doi = {10.1063/1.4829745},
Key = {Simmons:2013eg}
}
@article{fds331979,
Author = {Lo, MK and Akyildiz, HI and Dillon, E and Marcott, C and Roberts, AT and Everitt, HO and Jur, JS},
Title = {Depth profiling of trimethylaluminum modified PET fibers
with nanoscale infrared spectroscopy and imaging
techniques},
Journal = {Fiber Society 2014 Fall Meeting and Technical Conference:
Fibers for the Future},
Year = {2014},
Month = {January},
Abstract = {Depth profiling of poly(ethylene terephthalate) (PET) fibers
modified with trimethylaluminum (TMA) using transmission
electron microscopy (TEM), atomic force microscopy (AFM),
and atomic force microscope-based infrared spectroscopy
(AFM-IR).},
Key = {fds331979}
}
@article{fds331980,
Author = {Roberts, A and Binder, R and Kwong, NH and Golla, D and Cormode, D and LeRoy, BJ and Everitt, HO and Sandhu, A},
Title = {Probing electron-phonon interactions at the saddle point in
graphene},
Journal = {Conference on Lasers and Electro Optics Europe Technical
Digest},
Volume = {2014-January},
Year = {2014},
Month = {January},
ISBN = {9781557529992},
url = {http://dx.doi.org/10.1364/cleo_si.2014.sm3h.5},
Abstract = {High frequency differential transmission spectroscopy of
graphene, probing near the Mpoint, is performed and analyzed
theoretically. Electron-phonon coupling is identified as the
chief mechanism for renormalization with an effective
acoustic deformation potential of approximately
5eV.},
Doi = {10.1364/cleo_si.2014.sm3h.5},
Key = {fds331980}
}
@article{fds331978,
Author = {Sanz, JM and Ortiz, D and Alcaraz de la Osa and R and Saiz, JM and González, F and Brown, AS and Losurdo, M and Everitt, HO and Moreno,
F},
Title = {Metals for UV plasmonics},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
Abstract = {Electromagnetic enhancement of metallic nanoparticles on
substrates is assessed by an exhaustive numerical analysis.
The potential of each technologically promising metal for
UVplasmonic applications may be ascertained.© OSA
2014.},
Key = {fds331978}
}
@article{Mohanta:2013wp,
Author = {Mohanta, A and Simmons, JG and Everitt, HO and Shen, G and Margaret Kim,
S and Kung, P},
Title = {Effect of pressure and Al doping on structural and optical
properties of ZnO nanowires synthesized by chemical vapor
deposition},
Journal = {Journal of Luminescence},
Volume = {146},
Pages = {470-474},
Publisher = {Elsevier BV},
Year = {2014},
Month = {January},
ISSN = {0022-2313},
url = {http://www.sciencedirect.com/science/article/pii/S0022231313006728},
Abstract = {The effect of Al doping concentration and oxygen ambient
pressure on the structural and optical properties of
chemical vapor deposition-grown, Al-doped ZnO nanowires is
studied. As Al doping increases, the strength of the broad
visible emission band decreases and the UV emission
increases, but the growth rate depends on the oxygen
pressure in a complex manner. Together, these behaviors
suggest that Al doping is effective in reducing the number
of oxygen vacancies responsible for visible emission,
especially at low oxygen ambient pressure. The intensities
and quantum efficiencies of these emission mechanisms are
discussed in terms of the effect growth and doping
conditions have on the underlying excitonic decay
mechanisms. © 2013 Elsevier B.V.},
Doi = {10.1016/j.jlumin.2013.10.028},
Key = {Mohanta:2013wp}
}
@article{fds331982,
Author = {Golla, D and Roberts, A and Binder, R and Kwong, N and Yankowtiz, M and Cormode, D and LeRoy, B and Everitt, H and Sandhu,
A},
Title = {Time and energy resolved probing of many-body interactions
in graphene and heterostructures},
Journal = {Laser Science, Ls 2014},
Year = {2014},
Month = {January},
ISBN = {1557522863},
Abstract = {We studied the electron-phonon and electron-electron
interactions in graphene and its heterostructures using
pump-probe spectroscopy. Graphene on hexa-Boron Nitride
undergoes band structure modification, which affects the
relaxation mechanisms of the hot carriers. © 2014
OSA.},
Key = {fds331982}
}
@article{fds331984,
Author = {Roberts, A and Binder, R and Kwong, NH and Golla, D and Cormode, D and LeRoy, BJ and Everitt, HO and Sandhu, A},
Title = {Probing electron-phonon interactions at the saddle point in
graphene},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
ISBN = {9781557529992},
Abstract = {High frequency differential transmission spectroscopy of
graphene, probing near the Mpoint, is performed and analyzed
theoretically. Electron-phonon coupling is identified as the
chief mechanism for renormalization with an effective
acoustic deformation potential of approximately 5eV. © 2014
OSA.},
Key = {fds331984}
}
@article{fds331985,
Author = {Avrutin, V and Hafiz, SA and Zhang, F and Özgür, Ü and Bellotti, E and Bertazzi, F and Goano, M and Matulionis, A and Roberts, AT and Everitt,
HO and Morkoç, H},
Title = {Saga of efficiency degradation at high injection in InGaN
light emitting diodes},
Journal = {Turkish Journal of Physics},
Volume = {38},
Number = {3},
Pages = {269-313},
Publisher = {The Scientific and Technological Research Council of
Turkey},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.3906/fiz-1407-23},
Abstract = {What has turned into highly complex and somewhat
misunderstood efficiency loss mechanisms occurring in
light-emitting diodes (LEDs) based on the InN-GaN material
system at high injection levels are discussed. Suggestions
are made as to the dominant mechanism(s) in an open forum
format as well as pointing out some of the shortcomings of
the methodologies used and premises forwarded. It is
unequivocally known that increased junction temperature
would cause a reduction in radiative power due to mainly the
reduction in radiative recombination efficiency. Another
obvious mechanism is the asymmetry in doping in wide bandgap
semiconductors, such as GaN, wherein the hole concentration
lags well behind that of electrons in the active region.
Because an electron and a hole are required for radiative
recombination, the radiative efficiency cannot keep up with
increasing carrier injection due to progressively lagging
hole population. This results in either electron escape
without radiative recombination or electron accumulation,
which in turn changes the internal bias of the device,
manifested as reduced internal forward bias, which reduces
the rate of increase in light intensity. Some of the reports
ascribe the efficiency loss at high injection levels to
Auger recombination (mainly through indirect and recently
reportedly direct deductions) as the main and or the only
source of efficiency loss by in many cases simply relying on
the temperature and injection independent (not well taken)
A;B;C coefficients to fit a third order polynomial to the
efficiency vs. injection current. As for the direct
deduction, the spectroscopic analysis of Auger kicked hot
electrons as they traverse through the Γ and L bands before
being emitted into the vacuum by means of cesiated surface
challenges the existing theories and some experiments
regarding carrier scattering and Γ-L separation. Despite
just a few reports to the contrary, the bulk of the resonant
optical emission experiments do not support the Auger
argument as being the main cause. In parallel, there exists
a body of theoretical and experimental reports for electron
overow of ballistic/quasi-ballistic electrons traversing the
active region to p-GaN, escaping recombination altogether in
the active region. In fact and from the get go, the LED
industry ubiquitously employed, and continues to do so, an
(Al,In)GaN electron-blocking layer (EBL) to prevent electron
escape for improved light output that in and of itself would
more than suggest that the electron escape (overow) does
indeed occur. The only adverse effect of EBL is that it
impedes hole injection due to the valence band offset
between the p-type (Al,In)GaN EBL and p-GaN and also
generates piezoelectric (if not lattice matched) and
differential spontaneous polarization induced fields that
pull down the conduction band edge at the interface reducing
EBL's effectiveness. To at least reduce the aforementioned
aggravating factors to some extent, the electron overflow
and the associated efficiency loss can be reduced
substantially (particulars of which depend on the active
layer design) by inserting a stair-case electron injector
(SEI) with a step-like indium composition to act as an
"electron cooler" or by linearly graded cooler in some form
or another prior to the active region. Use of multiple
layered heterostructures for the active layers also plays
the role of electron cooler, albeit not necessarily in the
most optimum fashion. As if oblivious to the raging issues
alluded to above, the LED industry has been moving along
very successfully with a 2-prong approach. In one, dubbed
the "high voltage LED", a set of LEDs (most likely
configured in the form of a full-wave bridge rectifier)
operating at low currents, where the efficiency is at its
maximum, is used, which also has the added benefit of much
reduced power supply complexity and weight. The other is the
continual improvement of layer quality and optimum active
layer design, taking technological parameters into
consideration, which at the time of writing sported 63%
wall-plug efficiency at an injection current of 350 mA for
∼1.1 mm × 1.1 mm LEDs, which translates to approximately
75% efficiency once the voltage (about 3 V) and phosphor
conversion efficiencies are taken into account. Assuming the
same extraction and external quantum efficiencies, one
obtains about 86% for each. It would not be an exaggeration
to conclude that mid 90% internal quantum efficiencies are
very likely in play here, which means that the purported
inherent problems dominating the discussion are practically
reduced to an academic exercise. Despite aggravating factors
involving holes and hetero-barriers, commercial LEDs almost
invariably use multilayer hetero-structure designs for the
active layers, loosely termed as multiple quantum wells,
presumably to circumvent technological challenges and the
ramifications of the polarization induced field even though
double hetero-junction varieties could be preferable from
the point of view of hole transport. Eventually, the real
limiting factors are the extent of hole supply (can be
mitigated by increased hole concentration, which is well
known and continually explored) and the proverbial thermal
wall (can be mitigated by increased efficiency and efficient
heat removal) of course.},
Doi = {10.3906/fiz-1407-23},
Key = {fds331985}
}
@article{fds331981,
Author = {Roberts, A and Binder, R and Kwong, NH and Golla, D and Cormode, D and LeRoy, BJ and Everitt, HO and Sandhu, A},
Title = {Probing electron-phonon interactions at the saddle point in
graphene},
Journal = {Laser Science, Ls 2014},
Year = {2014},
Month = {January},
ISBN = {1557522863},
Abstract = {High frequency differential transmission spectroscopy of
graphene, probing near the Mpoint, is performed and analyzed
theoretically. Electron-phonon coupling is identified as the
chief mechanism for renormalization with an effective
acoustic deformation potential of approximately 5eV. © 2014
OSA.},
Key = {fds331981}
}
@article{fds324043,
Author = {Knight, MW and King, NS and Liu, L and Everitt, HO and Nordlander, P and Halas, NJ},
Title = {Aluminum for plasmonics.},
Journal = {Acs Nano},
Volume = {8},
Number = {1},
Pages = {834-840},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1021/nn405495q},
Abstract = {Unlike silver and gold, aluminum has material properties
that enable strong plasmon resonances spanning much of the
visible region of the spectrum and into the ultraviolet.
This extended response, combined with its natural abundance,
low cost, and amenability to manufacturing processes, makes
aluminum a highly promising material for commercial
applications. Fabricating Al-based nanostructures whose
optical properties correspond with theoretical predictions,
however, can be a challenge. In this work, the Al plasmon
resonance is observed to be remarkably sensitive to the
presence of oxide within the metal. For Al nanodisks, we
observe that the energy of the plasmon resonance is
determined by, and serves as an optical reporter of, the
percentage of oxide present within the Al. This
understanding paves the way toward the use of aluminum as a
low-cost plasmonic material with properties and potential
applications similar to those of the coinage
metals.},
Doi = {10.1021/nn405495q},
Key = {fds324043}
}
@article{fds350970,
Author = {Sanz, JM and Ortiz, D and Alcaraz de la Osa and R and Saiz, JM and González, F and Brown, AS and Losurdo, M and Everitt, HO and Moreno,
F},
Title = {Metals for UV plasmonics},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
ISBN = {9781557529954},
url = {http://dx.doi.org/10.1364/opm.2014.ow4d.3},
Abstract = {Electromagnetic enhancement of metallic nanoparticles on
substrates is assessed by an exhaustive numerical analysis.
The potential of each technologically promising metal for
UVplasmonic applications may be ascertained.© OSA
2014.},
Doi = {10.1364/opm.2014.ow4d.3},
Key = {fds350970}
}
@article{fds362544,
Author = {Roberts, A and Binder, R and Kwong, NH and Golla, D and Cormode, D and LeRoy, BJ and Everitt, HO and Sandhu, A},
Title = {Probing electron-phonon interactions at the saddle point in
graphene},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
ISBN = {9781557529992},
url = {http://dx.doi.org/10.1364/cleo_si.2014.sm3h.5},
Abstract = {High frequency differential transmission spectroscopy of
graphene, probing near the Mpoint, is performed and analyzed
theoretically. Electron-phonon coupling is identified as the
chief mechanism for renormalization with an effective
acoustic deformation potential of approximately 5eV. © 2014
OSA.},
Doi = {10.1364/cleo_si.2014.sm3h.5},
Key = {fds362544}
}
@article{Mrozack:2014ta,
Author = {Mrozack, Alex and Heimbeck, Martin and Marks, Daniel L and Richard, Jonathan and Everitt, Henry O and Brady, David
J.},
Title = {Compressive and Adaptive Millimeter-wave
SAR},
Journal = {arXiv.org},
Year = {2014},
Month = {February},
url = {http://arxiv.org/abs/1402.1466v1},
Abstract = {We apply adaptive sensing techniques to the problem of
locating sparse metallic scatterers using high-resolution,
frequency modulated continuous wave W-band RADAR. Using a
single detector, a frequency stepped source, and a lateral
translation stage, inverse synthetic aperture RADAR
reconstruction techniques are used to search for one or two
wire scatterers within a specified range, while an adaptive
algorithm determined successive sampling locations. The
two-dimensional location of each scatterer is thereby
identified with sub-wavelength accuracy in as few as 1/4 the
number of lateral steps required for a simple raster scan.
The implications of applying this approach to more complex
scattering geometries are explored in light of the various
assumptions made.},
Key = {Mrozack:2014ta}
}
@article{fds318415,
Author = {Roberts, AT and Binder, R and Kwong, NH and Golla, D and Cormode, D and LeRoy, BJ and Everitt, HO and Sandhu, A},
Title = {Optical characterization of electron-phonon interactions at
the saddle point in graphene.},
Journal = {Physical Review Letters},
Volume = {112},
Number = {18},
Pages = {187401},
Year = {2014},
Month = {May},
url = {http://dx.doi.org/10.1103/physrevlett.112.187401},
Abstract = {The role of many-body interactions is experimentally and
theoretically investigated near the saddle point absorption
peak of graphene. The time and energy-resolved differential
optical transmission measurements reveal the dominant role
played by electron-acoustic phonon coupling in band
structure renormalization. Using a Born approximation for
electron-phonon coupling and experimental estimates of the
dynamic lattice temperature, we compute the differential
transmission line shape. Comparing the numerical and
experimental line shapes, we deduce the effective acoustic
deformation potential to be Deff(ac)≃5 eV. This value
is in accord with recent theoretical predictions but differs
from those extracted using electrical transport
measurements.},
Doi = {10.1103/physrevlett.112.187401},
Key = {fds318415}
}
@article{fds318414,
Author = {Mrozack, A and Heimbeck, M and Marks, DL and Richard, J and Everitt, HO and Brady, DJ},
Title = {Adaptive millimeter-wave synthetic aperture imaging for
compressive sampling of sparse scenes.},
Journal = {Optics Express},
Volume = {22},
Number = {11},
Pages = {13515-13530},
Year = {2014},
Month = {June},
url = {http://dx.doi.org/10.1364/oe.22.013515},
Abstract = {We apply adaptive sensing techniques to the problem of
locating sparse metallic scatterers using high-resolution,
frequency modulated continuous wave W-band RADAR. Using a
single detector, a frequency stepped source, and a lateral
translation stage, inverse synthetic aperture RADAR
reconstruction techniques are used to search for one or two
wire scatterers within a specified range, while an adaptive
algorithm determined successive sampling locations. The
two-dimensional location of each scatterer is thereby
identified with sub-wavelength accuracy in as few as 1/4 the
number of lateral steps required for a simple raster scan.
The implications of applying this approach to more complex
scattering geometries are explored in light of the various
assumptions made.},
Doi = {10.1364/oe.22.013515},
Key = {fds318414}
}
@article{fds324838,
Author = {Yang, Y and Akozbek, N and Kim, TH and Sanz, JM and Moreno, F and Losurdo,
M and Brown, AS and Everitt, HO},
Title = {Ultraviolet-Visible Plasmonic Properties of Gallium
Nanoparticles Investigated by Variable-Angle Spectroscopic
and Mueller Matrix Ellipsometry},
Journal = {Acs Photonics},
Volume = {1},
Number = {7},
Pages = {582-589},
Publisher = {American Chemical Society (ACS)},
Year = {2014},
Month = {July},
url = {http://dx.doi.org/10.1021/ph500042v},
Abstract = {Self-assembled, irregular ensembles of hemispherical Ga
nanoparticles (NPs) were deposited on sapphire by molecular
beam epitaxy. These samples, whose constituent unimodal or
bimodal distribution of NP sizes was controlled by
deposition time, exhibited localized surface plasmon
resonances tunable from the ultraviolet to the visible
(UV/vis) spectral range. The optical response of each sample
was characterized using a variable-angle spectroscopic
ellipsometer, and the dielectric response of the ensemble of
NPs on each sample was parametrized using Lorentz
oscillators. From this, a relationship was found between NP
size and the deduced Lorentzian parameters (resonant
frequency, damping, oscillator strength) for most unimodal
and bimodal samples at most frequencies and angles of
incidence. However, for samples with a bimodal size
distribution, Mueller matrix ellipsometry revealed
nonspecular scattering at particular frequencies and angles,
suggesting a resonant interparticle coupling effect
consistent with recently observed strong local field
enhancements in the ultraviolet. (Graph presented).},
Doi = {10.1021/ph500042v},
Key = {fds324838}
}
@article{fds325476,
Author = {Akyildiz, HI and Roberts, AT and Everitt, HO and Jur,
JS},
Title = {Optical tuning of poly(ethylene terephthalate) by
organometallic vapor infiltration},
Journal = {Abstracts of Papers of the American Chemical
Society},
Volume = {248},
Pages = {1 pages},
Publisher = {AMER CHEMICAL SOC},
Year = {2014},
Month = {August},
Key = {fds325476}
}
@article{fds318416,
Author = {Kung, P and Mohanta, A and Simmons, JG and Everitt, HO and Shen, G and Waters, J and Kim, SM},
Title = {Synthesis and optical properties of undoped and aluminum
doped ZnO nanowires for optoelectronic nanodevice
applications},
Journal = {Proceedings 2014 Summer Topicals Meeting Series, Sum
2014},
Pages = {198-199},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479927678},
url = {http://dx.doi.org/10.1109/SUM.2014.108},
Abstract = {Zinc oxide (ZnO) is a major wide band gap semiconductor
material for optoelectronic and photonic devices because of
its exceptional optical properties, arising from the
combination of a wide band gap (&#x007E;3.37 eV) and a
large exciton binding energy (&#x007E;60 meV) [1].
One-dimensional ZnO nanostructures, such as nanowires and
nanorods, further exhibit unique properties that make them
attractive for Nan devices, especially in the ultraviolet
(UV) spectral range.},
Doi = {10.1109/SUM.2014.108},
Key = {fds318416}
}
@article{fds314115,
Author = {Kong, W and Mohanta, A and Roberts, AT and Jiao, WY and Fournelle, J and Kim, TH and Losurdo, M and Everitt, HO and Brown,
AS},
Title = {Room temperature photoluminescence from InxAl(1-x)N
films deposited by plasma-assisted molecular beam
epitaxy},
Journal = {Applied Physics Letters},
Volume = {105},
Number = {13},
Pages = {132101-132101},
Publisher = {AIP Publishing},
Year = {2014},
Month = {September},
ISSN = {0003-6951},
url = {http://dx.doi.org/10.1063/1.4896849},
Abstract = {InAlN films deposited by plasma-assisted molecular beam
epitaxy exhibited a lateral composition modulation
characterized by 10-12 nm diameter, honeycomb-shaped,
columnar domains with Al-rich cores and In-rich boundaries.
To ascertain the effect of this microstructure on its
optical properties, room temperature absorption and
photoluminescence characteristics of InxAl(1-x)N were
comparatively investigated for indium compositions ranging
from x = 0.092 to 0.235, including x = 0.166 lattice matched
to GaN. The Stokes shift of the emission was significantly
greater than reported for films grown by metalorganic
chemical vapor deposition, possibly due to the phase
separation in these nanocolumnar domains. The room
temperature photoluminescence also provided evidence of
carrier transfer from the InAlN film to the GaN
template.},
Doi = {10.1063/1.4896849},
Key = {fds314115}
}
@article{fds350862,
Author = {Roberts, A and Binder, R and Kwong, NH and Golla, D and Cormode, D and LeRoy, BJ and Everitt, HO and Sandhu, A},
Title = {Probing electron-phonon interactions at the saddle point in
graphene},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {October},
ISBN = {1557522863},
url = {http://dx.doi.org/10.1364/ls.2014.ltu4i.3},
Abstract = {High frequency differential transmission spectroscopy of
graphene, probing near the Mpoint, is performed and analyzed
theoretically. Electron-phonon coupling is identified as the
chief mechanism for renormalization with an effective
acoustic deformation potential of approximately 5eV. © 2014
OSA.},
Doi = {10.1364/ls.2014.ltu4i.3},
Key = {fds350862}
}
@article{fds350619,
Author = {Golla, D and Roberts, A and Binder, R and Kwong, N and Yankowtiz, M and Cormode, D and LeRoy, B and Everitt, H and Sandhu,
A},
Title = {Time and energy resolved probing of many-body interactions
in graphene and heterostructures},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {October},
ISBN = {1557522863},
url = {http://dx.doi.org/10.1364/ls.2014.ltu4i.4},
Abstract = {We studied the electron-phonon and electron-electron
interactions in graphene and its heterostructures using
pump-probe spectroscopy. Graphene on hexa-Boron Nitride
undergoes band structure modification, which affects the
relaxation mechanisms of the hot carriers. © 2014
OSA.},
Doi = {10.1364/ls.2014.ltu4i.4},
Key = {fds350619}
}
@article{fds325474,
Author = {Akyildiz, HI and Lo, M and Dillon, E and Roberts, AT and Everitt, HO and Jur, JS},
Title = {Formation of novel photoluminescent hybrid materials by
sequential vapor infiltration into polyethylene
terephthalate fibers},
Journal = {Journal of Materials Research},
Volume = {29},
Number = {23},
Pages = {2817-2826},
Publisher = {Cambridge University Press (CUP)},
Year = {2014},
Month = {November},
url = {http://dx.doi.org/10.1557/jmr.2014.333},
Abstract = {Fibrous polyethylene terephthalate (PET) was modified by
organometallic vapor exposure to form hybrid materials with
unique photoluminescent characteristics. Using a sequential
vapor infiltration (SVI) process, the elongated exposures of
trimethylaluminum (TMA) to PET were examined. As the
infiltration temperature increased, the evidence of changes
in the reaction between the organometallic vapor and the
polymer was observed as well as significant changes in the
infiltration depth into the polymer fiber, owing to the
variation in the reaction mechanisms of the hybrid material
formation. At TMA exposures of 60 °C, the mass of the
polymer fiber increased by ∼55 wt%, whereas exposures at
150 °C were limited to ∼25 wt% infiltration.
Photoluminescence analysis of PET after TMA infiltration
shows an intensity increase of up to ∼13x and an increase
in red shift with increasing infiltration temperature,
attributed to the variations in the reaction mechanism to
form the hybrid modification observed through the
spectroscopy analysis.},
Doi = {10.1557/jmr.2014.333},
Key = {fds325474}
}
@article{fds331983,
Author = {Hokmabadi, MP and Heimbeck, MS and Wilbert, DS and Kung, P and Everitt,
HO and Kim, SM},
Title = {Polarization controllable THz stereometamaterial
absorber},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISBN = {9781479938773},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2014.6956184},
Abstract = {Spatially different arrangements of identical metaatoms in a
unit cell bring about distinct properties in
stereometamaterials. Integrating the stereometamaterial into
a perfect metamaterial absorber, we designed, fabricated,
and characterized a device with single or double band
absorption responses and an absorption/reflection switching
characteristic dependent upon the polarization of the
incident THz wave. Two non-concentric Cu rings tightly
coupled via a polyimide layer form the stereometamaterial
frequency selective surface (FSS). The FSS is placed on
another polyimide layer deposited on a Cu backplane. Despite
the rotational symmetry of the rings, non-centricity breaks
the reflection symmetry of the FSS, leading to a unique
interaction between the rings and a Cu backplane.
Interaction between dipoles on an FSS and their mirror
images due to Cu backplane is studied to gain a better
understanding of this device.},
Doi = {10.1109/IRMMW-THz.2014.6956184},
Key = {fds331983}
}
@article{fds324839,
Author = {Heimbeck, MS and Ng, WR and Golish, DR and Gehm, ME and Everitt,
HO},
Title = {Terahertz digital holographic imaging of visibly opaque
printed dielectrics},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISBN = {9781479938773},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2014.6956276},
Abstract = {Terahertz digital off-axis holography has been demonstrated
as a non-destructive imaging tool for three-dimensional (3D)
printed structures. Digital holographic reconstructions from
two structures were used to measure the imager's modulation
transfer function and to show that terahertz digital
holography can provide submillimeter resolution images of
visually opaque printed structures and map their interior.
As a demonstration we report on the detection of embedded
air voids and material inclusions that differ from the host
material in their complex refractive indices.},
Doi = {10.1109/IRMMW-THz.2014.6956276},
Key = {fds324839}
}
@article{fds325475,
Author = {Tanner, EA and Phillips, DJ and Persons, CM and De Lucia and FC and Everitt, HO},
Title = {Design and signature analysis of remote trace-gas
identification methodology based on infrared-terahertz
double-resonance spectroscopy},
Journal = {Physical Review Applied},
Volume = {2},
Number = {5},
Publisher = {American Physical Society (APS)},
Year = {2014},
Month = {November},
url = {http://dx.doi.org/10.1103/PhysRevApplied.2.054016},
Abstract = {The practicality of a newly proposed infrared-terahertz
(IR-THz) double-resonance (DR) spectroscopic technique for
remote trace-gas identification is explored. The strength of
the DR signatures depends on known molecular parameters from
which a combination of pump-probe transitions may be
identified to recognize a specific analyte. Atmospheric
pressure broadening of the IR and THz trace-gas spectra
relaxes the stringent pump coincidence requirement, allowing
many DR signatures to be excited, some of which occur in the
favorable atmospheric transmission windows below 500 GHz. By
designing the DR spectrometer and performing a detailed
signal analysis, the pump-probe power requirements for
detecting trace amounts of methyl fluoride, methyl chloride,
or methyl bromide may be estimated for distances up to 1 km.
The strength of the DR signature increases linearly with
pump intensity but only as the square root of the probe
power because the received signal is in the Townes noise
limit. The concept of a specificity matrix is introduced and
used to quantify the recognition specificity and calculate
the probability of false positive detection of an
interferent.},
Doi = {10.1103/PhysRevApplied.2.054016},
Key = {fds325475}
}
@article{fds318413,
Author = {Heimbeck, MS and Ng, WR and Golish, DR and Gehm, ME and Everitt,
HO},
Title = {Terahertz digital holographic imaging of voids within
visibly opaque dielectrics},
Journal = {Ieee Transactions on Terahertz Science and
Technology},
Volume = {5},
Number = {1},
Pages = {110-116},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {January},
url = {http://dx.doi.org/10.1109/TTHZ.2014.2364511},
Abstract = {Terahertz digital off-axis holography (THzDH) has been
demonstrated as a non-destructive tool for imaging voids
within visually opaque dielectrics. Using a raster scanning
heterodyne detector, the imager captures lensless
transmission holograms formed by the interaction of a highly
coherent, monochromatic beam with 3-D printed structures.
Digital hologram reconstructions from two structures were
used to measure the imager's modulation transfer function
and to show that terahertz digital holography can provide
sub-millimeter resolution images of voids within visually
opaque printed structures. As a demonstration we imaged
embedded air- and lossy dielectric filled-voids whose
refractive indices differ from the host material.},
Doi = {10.1109/TTHZ.2014.2364511},
Key = {fds318413}
}
@article{fds339293,
Author = {Everitt, HO and De Lucia and FC},
Title = {Detection and recognition of explosives using
terahertz-frequency spectroscopic techniques},
Pages = {323-346},
Booktitle = {Laser-Based Optical Detection of Explosives},
Year = {2015},
Month = {January},
ISBN = {9781138748057},
Abstract = {This chapter considers the challenge of using terahertz
(THz) techniques for the detection and recognition of
explosives. There are two general approaches to this
problem: (1) imaging, which uses the penetration capability
of THz radiation to “see” the image of the explosive,
and (2) spectroscopy, which allows the chemical signature to
be recognized. The former is beyond the scope of this volume
and has been well addressed previously. The latter can be
divided into two subcategories: the detection and
recognition of the explosive itself and the detection and
recognition of its precursors, additives, or decay products.
Most reports claiming detection of these materials,
hereafter collectively called “explosives,” have only
considered laboratory measurements of them in pure form and
have not considered the greater challenge of recognizing
these materials among naturally occurring compounds or mixed
with other compounds and shielded in containers. When these
challenges are considered seriously, the exquisite
recognition specificity afforded by gas-phase THz
spectroscopy may only be used to detect and recognize
explosives in very limited circumstances.},
Key = {fds339293}
}
@article{fds324836,
Author = {Knight, MW and Coenen, T and Yang, Y and Brenny, BJM and Losurdo, M and Brown, AS and Everitt, HO and Polman, A},
Title = {Gallium plasmonics: deep subwavelength spectroscopic imaging
of single and interacting gallium nanoparticles.},
Journal = {Acs Nano},
Volume = {9},
Number = {2},
Pages = {2049-2060},
Year = {2015},
Month = {February},
url = {http://dx.doi.org/10.1021/nn5072254},
Abstract = {Gallium has recently been demonstrated as a phase-change
plasmonic material offering UV tunability, facile synthesis,
and a remarkable stability due to its thin, self-terminating
native oxide. However, the dense irregular nanoparticle (NP)
ensembles fabricated by molecular-beam epitaxy make optical
measurements of individual particles challenging. Here we
employ hyperspectral cathodoluminescence (CL) microscopy to
characterize the response of single Ga NPs of various sizes
within an irregular ensemble by spatially and spectrally
resolving both in-plane and out-of-plane plasmonic modes.
These modes, which include hybridized dipolar and
higher-order terms due to phase retardation and substrate
interactions, are correlated with finite difference time
domain (FDTD) electrodynamics calculations that consider the
Ga NP contact angle, substrate, and native Ga/Si surface
oxidation. This study experimentally confirms previous
theoretical predictions of plasmonic size-tunability in
single Ga NPs and demonstrates that the plasmonic modes of
interacting Ga nanoparticles can hybridize to produce strong
hot spots in the ultraviolet. The controlled, robust UV
plasmonic resonances of gallium nanoparticles are applicable
to energy- and phase-specific applications such as optical
memory, environmental remediation, and simultaneous
fluorescence and surface-enhanced Raman spectroscopies.},
Doi = {10.1021/nn5072254},
Key = {fds324836}
}
@article{fds324837,
Author = {Watson, AM and Zhang, X and Alcaraz de la Osa and R and Marcos Sanz and J and González, F and Moreno, F and Finkelstein, G and Liu, J and Everitt,
HO},
Title = {Rhodium nanoparticles for ultraviolet plasmonics.},
Journal = {Nano Letters},
Volume = {15},
Number = {2},
Pages = {1095-1100},
Year = {2015},
Month = {February},
url = {http://dx.doi.org/10.1021/nl5040623},
Abstract = {The nonoxidizing catalytic noble metal rhodium is introduced
for ultraviolet plasmonics. Planar tripods of 8 nm Rh
nanoparticles, synthesized by a modified polyol reduction
method, have a calculated local surface plasmon resonance
near 330 nm. By attaching p-aminothiophenol, local
field-enhanced Raman spectra and accelerated photodamage
were observed under near-resonant ultraviolet illumination,
while charge transfer simultaneously increased fluorescence
for up to 13 min. The combined local field enhancement and
charge transfer demonstrate essential steps toward
plasmonically enhanced ultraviolet photocatalysis.},
Doi = {10.1021/nl5040623},
Key = {fds324837}
}
@article{fds331977,
Author = {McClain, MJ and Schlather, AE and Ringe, E and King, NS and Liu, L and Manjavacas, A and Knight, MW and Kumar, I and Whitmire, KH and Everitt,
HO and Nordlander, P and Halas, NJ},
Title = {Aluminum nanocrystals.},
Journal = {Nano Letters},
Volume = {15},
Number = {4},
Pages = {2751-2755},
Year = {2015},
Month = {April},
url = {http://dx.doi.org/10.1021/acs.nanolett.5b00614},
Abstract = {We demonstrate the facile synthesis of high purity aluminum
nanocrystals over a range of controlled sizes from 70 to 220
nm diameter with size control achieved through a simple
modification of solvent ratios in the reaction solution. The
monodisperse, icosahedral, and trigonal bipyramidal
nanocrystals are air-stable for weeks, due to the formation
of a 2-4 nm thick passivating oxide layer on their surfaces.
We show that the nanocrystals support size-dependent
ultraviolet and visible plasmon modes, providing a far more
sustainable alternative to gold and silver nanoparticles
currently in widespread use.},
Doi = {10.1021/acs.nanolett.5b00614},
Key = {fds331977}
}
@article{fds331976,
Author = {Alcaraz De La Osa and R and Sanz, JM and Barreda, AI and Saiz, JM and González, F and Everitt, HO and Moreno, F},
Title = {Rhodium Tripod Stars for UV Plasmonics},
Journal = {The Journal of Physical Chemistry C},
Volume = {119},
Number = {22},
Pages = {12572-12580},
Publisher = {American Chemical Society (ACS)},
Year = {2015},
Month = {June},
url = {http://dx.doi.org/10.1021/acs.jpcc.5b00983},
Abstract = {Local field enhancements produced by metal nanoparticles
have been widely investigated in the visible range for
common metals like gold and silver, but recent interest in
ultraviolet plasmonics has required consideration of
alternate metals. Aluminum and gallium are particularly
attractive, but the native oxide that forms on them consumes
the metal in the smallest nanoparticles and limits the
usefulness of larger nanoparticles for applications that
require contact with a bare metal surface. The widely used
catalyst rhodium is a noble metal that forms no native oxide
under normal atmospheric conditions and has recently been
shown to exhibit UV plasmonic behavior. Here we analyze the
plasmonic properties of the most easily synthesized rhodium
nanoparticle shapes and sizes and compare them to other UV
plasmonic metals. Of particular interest is the tripod star
monomer and dimer, for which we show the dependence of the
absorption cross-section and the local electric field
intensity on the constituent size and shape of tripod arms,
and the gap distance in dimers, in representative dielectric
hosts. It is shown that rhodium nanoparticles are
particularly compelling for UV plasmonic applications
requiring nanoparticles smaller than 20 nm. (Figure
Presented).},
Doi = {10.1021/acs.jpcc.5b00983},
Key = {fds331976}
}
@article{fds331975,
Author = {Kong, W and Roberts, AT and Jiao, WY and Fournelle, J and Kim, TH and Losurdo, M and Everitt, HO and Brown, AS},
Title = {Room temperature Ultraviolet B emission from InAlGaN films
synthesized by plasma-assisted molecular beam
epitaxy},
Journal = {Applied Physics Letters},
Volume = {107},
Number = {13},
Pages = {132102-132102},
Publisher = {AIP Publishing},
Year = {2015},
Month = {September},
url = {http://dx.doi.org/10.1063/1.4931942},
Abstract = {Thin films of the wide bandgap quaternary semiconductor
In<inf>x</inf>Al<inf>y</inf>Ga<inf>(1-x-y)</inf>N with low
In (x=0.01-0.05) and high Al composition (y=0.40-0.49) were
synthesized on GaN templates by plasma-assisted molecular
beam epitaxy. High-resolution X-ray diffraction was used to
correlate the strain accommodation of the films to
composition. Room temperature ultraviolet B (280nm-320nm)
photoluminescence intensity increased with increasing In
composition, while the Stokes shift remained relatively
constant. The data suggest a competition between radiative
and non-radiative recombination occurs for carriers,
respectively, localized at centers produced by In
incorporation and at dislocations produced by strain
relaxation.},
Doi = {10.1063/1.4931942},
Key = {fds331975}
}
@article{fds331974,
Author = {King, NS and Liu, L and Yang, X and Cerjan, B and Everitt, HO and Nordlander, P and Halas, NJ},
Title = {Fano Resonant Aluminum Nanoclusters for Plasmonic
Colorimetric Sensing.},
Journal = {Acs Nano},
Volume = {9},
Number = {11},
Pages = {10628-10636},
Publisher = {American Chemical Society (ACS)},
Year = {2015},
Month = {November},
url = {http://dx.doi.org/10.1021/acsnano.5b04864},
Abstract = {Aluminum is an abundant and high-quality material for
plasmonics with potential for large-area, low-cost photonic
technologies. Here we examine aluminum nanoclusters with
plasmonic Fano resonances that can be tuned from the near-UV
into the visible region of the spectrum. These nanoclusters
can be designed with specific chromaticities in the
blue-green region of the spectrum and exhibit a remarkable
spectral sensitivity to changes in the local dielectric
environment. We show that such structures can be used quite
generally for colorimetric localized surface plasmon
resonance (LSPR) sensing, where the presence of analytes is
detected by directly observable color changes rather than
through photodetectors and spectral analyzers. To quantify
our results and provide a metric for optimization of such
structures for colorimetric LSPR sensing, we introduce a
figure of merit based on the color perception ability of the
human eye.},
Doi = {10.1021/acsnano.5b04864},
Key = {fds331974}
}
@article{fds372053,
Author = {Holland, G and Everitt, H},
Title = {Delirium recovery programme: cognitive enablement at home
following hospital admission},
Journal = {British Journal of Occupational Therapy},
Volume = {79},
Pages = {129-129},
Year = {2016},
Key = {fds372053}
}
@article{fds331972,
Author = {Zhang, X and Gutierrez, Y and Li, P and Barreda, AI and Watson, AM and Alcaraz De La Osa and R and Finkelstein, G and Gonzalez, F and Ortiz, D and Saiz, JM and Sanz, JM and Everitt, HO and Liu, J and Moreno,
F},
Title = {Plasmonics in the UV range with Rhodium nanocubes},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9884},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510601291},
url = {http://dx.doi.org/10.1117/12.2227674},
Abstract = {Plasmonics in the UV-range constitutes a new challenge due
to the increasing demand to detect, identify and destroy
biological toxins, enhance biological imaging, and
characterize semiconductor devices at the nanometer scale.
Silver and aluminum have an effcient plasmonic performance
in the near UV region, but oxidation reduces its performance
in this range. Recent studies point out rhodium as one of
the most promising metals for this purpose: it has a good
plasmonic response in the UV and, as gold in the visible, it
presents a low tendency to oxidation. Moreover, its easy
fabrication through chemical means and its potential for
photocatalytic applications, makes this material very
attractive for building plasmonic tools in the UV. In this
work, we will show an overview of our recent collaborative
research with rhodium nanocubes (NC) for Plasmonics in the
UV.},
Doi = {10.1117/12.2227674},
Key = {fds331972}
}
@article{fds331973,
Author = {Zhang, X and Li, P and Barreda, Á and Gutiérrez, Y and González, F and Moreno, F and Everitt, HO and Liu, J},
Title = {Size-tunable rhodium nanostructures for wavelength-tunable
ultraviolet plasmonics.},
Journal = {Nanoscale Horizons},
Volume = {1},
Number = {1},
Pages = {75-80},
Publisher = {Royal Society of Chemistry (RSC)},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.1039/c5nh00062a},
Abstract = {Polydisperse rhodium nanoparticles have recently shown
promise for ultraviolet (UV) plasmonics, but controlling the
size and morphology of metal nanoparticles is essential for
tuning surface plasmon resonances. Here we report the use of
slow-injection polyol methods to synthesize monodisperse Rh
nanocubes with unprecedentedly large sizes and slightly
concave faces. The associated local surface plasmon
resonances (LSPRs) red-shifted with increasing sizes in the
UV region from deep UV to around 400 nm, consistent with
numerical simulations. UV illumination of p-aminothiophenol
attached to the Rh nanocubes generated surface-enhanced
Raman spectra and accelerated photo-decomposition, and these
enhancements were largest for nanocubes whose LSPR was
resonant with the UV laser. The lack of a native oxide
coating, the precise control of nanocube size and morphology
demonstrated here, and the ability to tune the surface
plasmon resonance from the deep UV to near UV spectral
region, make rhodium a compelling choice for UV plasmonic
applications.},
Doi = {10.1039/c5nh00062a},
Key = {fds331973}
}
@article{fds342767,
Author = {Karl, N and Heimbeck, MS and Everitt, HO and Chen, H-T and Taylor, AJ and Benz, A and Reno, JL and Brener, I and Mendis, R and Mittleman,
DM},
Title = {Theoretical and Experimental Determination of Surface
Susceptibility of Switchable Terahertz Metasurfaces},
Journal = {2016 Progress in Electromagnetics Research Symposium
(Piers)},
Pages = {706-707},
Publisher = {IEEE},
Year = {2016},
Month = {January},
Key = {fds342767}
}
@article{fds365849,
Author = {Binder, R and Roberts, A and Kwong, NH and Sandhu, A and Everitt,
HO},
Title = {Global k-Space Analysis of Electron-Phonon Interaction in
Graphene},
Journal = {Optics Infobase Conference Papers},
Year = {2016},
Month = {January},
ISBN = {9781557528209},
Abstract = {Electron-phonon coupling in graphene is studied across the
Brillouin zone. The contributions from modulated hopping and
conventional deformation potential coupling, and from
intraband and interband coupling are analyzed and related to
available experimental M-point spectroscopy.},
Key = {fds365849}
}
@article{fds331971,
Author = {Zhou, L and Zhang, C and McClain, MJ and Manjavacas, A and Krauter, CM and Tian, S and Berg, F and Everitt, HO and Carter, EA and Nordlander, P and Halas, NJ},
Title = {Aluminum Nanocrystals as a Plasmonic Photocatalyst for
Hydrogen Dissociation.},
Journal = {Nano Letters},
Volume = {16},
Number = {2},
Pages = {1478-1484},
Publisher = {American Chemical Society (ACS)},
Year = {2016},
Month = {February},
url = {http://dx.doi.org/10.1021/acs.nanolett.5b05149},
Abstract = {Hydrogen dissociation is a critical step in many
hydrogenation reactions central to industrial chemical
production and pollutant removal. This step typically
utilizes the favorable band structure of precious metal
catalysts like platinum and palladium to achieve high
efficiency under mild conditions. Here we demonstrate that
aluminum nanocrystals (Al NCs), when illuminated, can be
used as a photocatalyst for hydrogen dissociation at room
temperature and atmospheric pressure, despite the high
activation barrier toward hydrogen adsorption and
dissociation. We show that hot electron transfer from Al NCs
to the antibonding orbitals of hydrogen molecules
facilitates their dissociation. Hot electrons generated from
surface plasmon decay and from direct photoexcitation of the
interband transitions of Al both contribute to this process.
Our results pave the way for the use of aluminum, an
earth-abundant, nonprecious metal, for photocatalysis.},
Doi = {10.1021/acs.nanolett.5b05149},
Key = {fds331971}
}
@article{fds325473,
Author = {Binder, R and Roberts, AT and Kwong, NH and Sandhu, A and Everitt,
HO},
Title = {Global k -space analysis of electron-phonon interaction in
graphene and application to M -point spectroscopy},
Journal = {Physical Review B},
Volume = {93},
Number = {8},
Publisher = {American Physical Society (APS)},
Year = {2016},
Month = {February},
url = {http://dx.doi.org/10.1103/PhysRevB.93.085414},
Abstract = {Recently, optical probes have become available that can
access and observe energy renormalization due to
electron-phonon interaction in graphene away from the
well-studied Dirac K point. Using an expanded deformation
potential approach, we present a theoretical study of the
electron-phonon self-energy and scattering matrix elements
across the entire Brillouin zone. We elucidate the roles of
modulated hopping and conventional deformation potential
coupling, parameterized via standard deformation potentials,
the in-plane phonon modes, intra- and interband
contributions, and umklapp processes. Applying the theory to
nonlinear optical transmission spectroscopy in the vicinity
of the M point, we find very good agreement with recently
published experimental data.},
Doi = {10.1103/PhysRevB.93.085414},
Key = {fds325473}
}
@article{fds325472,
Author = {Reish, ME and Zhang, Z and Ma, S and Harrison, I and Everitt,
HO},
Title = {How Annealing and Charge Scavengers Affect Visible Emission
from ZnO Nanocrystals},
Journal = {The Journal of Physical Chemistry C},
Volume = {120},
Number = {9},
Pages = {5108-5113},
Publisher = {American Chemical Society (ACS)},
Year = {2016},
Month = {March},
url = {http://dx.doi.org/10.1021/acs.jpcc.5b12094},
Abstract = {Simultaneous transmission infrared (IR) absorption and
photoluminescence (PL) spectroscopies are used to reveal the
correlation of free electron and defect densities during the
stepwise annealing of ZnO nanocrystals in high vacuum. For
increasing annealing temperatures between 700 and 1000 K,
the free electron density increases with a negligible
increase in PL yield. With increased annealing temperature
above 1000 K, the free electron density decreases and the PL
yield increases in inverse proportion. Accompanying the free
electron loss are indications of increased bound charges and
changes in the multiphonon bands in the infrared spectrum,
which collectively suggest that structural change and defect
formation accompanies the loss of free electrons and the
increase in PL. Exposure of the previously annealed sample
to electron (O2) and hole (MeOH) scavengers shows that the
buildup of holes quenches visible emission, while additional
electrons have a marginal effect on the PL yield. Given that
certain neutral donors bind excitons and facilitate energy
transfer to visible emitting sites, the buildup of free
holes appears to quench PL intensity by ionizing those
neutral donors.},
Doi = {10.1021/acs.jpcc.5b12094},
Key = {fds325472}
}
@article{fds325471,
Author = {Alabastri, A and Yang, X and Manjavacas, A and Everitt, HO and Nordlander, P},
Title = {Extraordinary Light-Induced Local Angular Momentum near
Metallic Nanoparticles.},
Journal = {Acs Nano},
Volume = {10},
Number = {4},
Pages = {4835-4846},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1021/acsnano.6b01851},
Abstract = {The intense local field induced near metallic nanostructures
provides strong enhancements for surface-enhanced
spectroscopies, a major focus of plasmonics research over
the past decade. Here we consider that plasmonic
nanoparticles can also induce remarkably large
electromagnetic field gradients near their surfaces.
Sizeable field gradients can excite dipole-forbidden
transitions in nearby atoms or molecules and provide unique
spectroscopic fingerprinting for chemical and bimolecular
sensing. Specifically, we investigate how the local field
gradients near metallic nanostructures depend on geometry,
polarization, and wavelength. We introduce the concept of
the local angular momentum (LAM) vector as a useful figure
of merit for the design of nanostructures that provide large
field gradients. This quantity, based on integrated fields
rather than field gradients, is particularly well-suited for
optimization using numerical grid-based full wave
electromagnetic simulations. The LAM vector has a more
compact structure than the gradient matrix and can be
straightforwardly associated with the angular momentum of
the electromagnetic field incident on the plasmonic
structures.},
Doi = {10.1021/acsnano.6b01851},
Key = {fds325471}
}
@article{fds331970,
Author = {Zubair, A and Tsentalovich, DE and Young, CC and Heimbeck, MS and Everitt, HO and Pasquali, M and Kono, J},
Title = {Carbon nanotube fiber terahertz polarizer},
Journal = {Applied Physics Letters},
Volume = {108},
Number = {14},
Pages = {141107-141107},
Publisher = {AIP Publishing},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1063/1.4945708},
Abstract = {Conventional, commercially available terahertz (THz)
polarizers are made of uniformly and precisely spaced
metallic wires. They are fragile and expensive, with
performance characteristics highly reliant on wire diameters
and spacings. Here, we report a simple and highly
error-tolerant method for fabricating a freestanding THz
polarizer with nearly ideal performance, reliant on the
intrinsically one-dimensional character of conduction
electrons in well-aligned carbon nanotubes (CNTs). The
polarizer was constructed on a mechanical frame over which
we manually wound acid-doped CNT fibers with ultrahigh
electrical conductivity. We demonstrated that the polarizer
has an extinction ratio of ∼-30 dB with a low insertion
loss (<0.5 dB) throughout a frequency range of 0.2-1.1 THz.
In addition, we used a THz ellipsometer to measure the
Müller matrix of the CNT-fiber polarizer and found
comparable attenuation to a commercial metallic wire-grid
polarizer. Furthermore, based on the classical theory of
light transmission through an array of metallic wires, we
demonstrated the most striking difference between the
CNT-fiber and metallic wire-grid polarizers: the latter
fails to work in the zero-spacing limit, where it acts as a
simple mirror, while the former continues to work as an
excellent polarizer even in that limit due to the
one-dimensional conductivity of individual
CNTs.},
Doi = {10.1063/1.4945708},
Key = {fds331970}
}
@article{fds325470,
Author = {Akyildiz, HI and Stano, KL and Roberts, AT and Everitt, HO and Jur,
JS},
Title = {Photoluminescence Mechanism and Photocatalytic Activity of
Organic-Inorganic Hybrid Materials Formed by Sequential
Vapor Infiltration.},
Journal = {Langmuir : the Acs Journal of Surfaces and
Colloids},
Volume = {32},
Number = {17},
Pages = {4289-4296},
Year = {2016},
Month = {May},
url = {http://dx.doi.org/10.1021/acs.langmuir.6b00285},
Abstract = {Organic-inorganic hybrid materials formed by sequential
vapor infiltration (SVI) of trimethylaluminum into polyester
fibers are demonstrated, and the photoluminescence of the
fibers is evaluated using a combined UV-vis and
photoluminescence excitation (PLE) spectroscopy approach.
The optical activity of the modified fibers depends on
infiltration thermal processing conditions and is attributed
to the reaction mechanisms taking place at different
temperatures. At low temperatures a single excitation band
and dual emission bands are observed, while, at high
temperatures, two distinct absorption bands and one emission
band are observed, suggesting that the physical and chemical
structure of the resulting hybrid material depends on the
SVI temperature. Along with enhancing the photoluminescence
intensity of the PET fibers, the internal quantum efficiency
also increased to 5-fold from ∼4-5% to ∼24%. SVI
processing also improved the photocatalytic activity of the
fibers, as demonstrated by photodeposition of Ag and Au
metal particles out of an aqueous metal salt solution onto
fiber surfaces via UVA light exposure. Toward applications
in flexible electronics, well-defined patterning of the
metallic materials is achieved by using light masking and
focused laser rastering approaches.},
Doi = {10.1021/acs.langmuir.6b00285},
Key = {fds325470}
}
@article{fds331969,
Author = {Heimbeck, MS and Everitt, HO},
Title = {Off-axis Fresnel digital holography at terahertz
frequencies},
Journal = {Optics Infobase Conference Papers},
Publisher = {OSA},
Year = {2016},
Month = {July},
ISBN = {9781943580156},
url = {http://dx.doi.org/10.1364/DH.2016.DW2E.2},
Abstract = {An Off-axis Fresnel interferometric imager was constructed
to acquire holograms using a highly coherent, narrowband,
continuous wave source tunable over 0.3-1.0 THz. Fresnel and
angular spectrum reconstruction methods of amplitude and
phase holograms are presented and compared. While transverse
resolution was on the order of the wavelength, unprecedented
depth resolution of nearly λ/300 (2 μm) is
reported.},
Doi = {10.1364/DH.2016.DW2E.2},
Key = {fds331969}
}
@article{fds325469,
Author = {Gutierrez, Y and Ortiz, D and Sanz, JM and Saiz, JM and Gonzalez, F and Everitt, HO and Moreno, F},
Title = {How an oxide shell affects the ultraviolet plasmonic
behavior of Ga, Mg, and Al nanostructures.},
Journal = {Optics Express},
Volume = {24},
Number = {18},
Pages = {20621-20631},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1364/oe.24.020621},
Abstract = {The ultraviolet (UV) range presents new challenges for
plasmonics, with interesting applications ranging from
engineering to biology. In previous research, gallium,
aluminum, and magnesium were found to be very promising UV
plasmonic metals. However, a native oxide shell surrounds
nanostructures of these metals that affects their plasmonic
response. Here, through a nanoparticle-oxide core-shell
model, we present a detailed electromagnetic analysis of how
oxidation alters the UV-plasmonic response of spherical or
hemisphere-on-substrate nanostructures made of those metals
by analyzing the spectral evolution of two parameters: the
absorption efficiency (far-field analysis) and the
enhancement of the local intensity averaged over the
nanoparticle surface (near-field analysis).},
Doi = {10.1364/oe.24.020621},
Key = {fds325469}
}
@article{fds331968,
Author = {Karl, N and Heimbeck, M and Everitt, H and Chen, HT and Taylor, AJ and Benz, A and Reno, JL and Brener, I and Mendis, R and Mittleman,
DM},
Title = {Characterization of switchable terahertz
metasurfaces},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Volume = {2016-November},
Publisher = {IEEE},
Year = {2016},
Month = {November},
ISBN = {9781467384858},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2016.7758758},
Abstract = {We describe experimental characterization of switchable THz
metasurfaces using variable-angle broadband THz
ellipsometry. A theoretical framework is used to extract
surface susceptibility tensors as a function of frequency
and applied DC bias. This will allow us to make a priori
predictions of the performance of these devices for
applications as metasurface active components.},
Doi = {10.1109/IRMMW-THz.2016.7758758},
Key = {fds331968}
}
@article{fds331967,
Author = {Binder, R and Roberts, A and Kwong, NH and Sandhu, A and Everitt,
HO},
Title = {Global k-space analysis of electron-phonon interaction in
graphene},
Journal = {2016 Conference on Lasers and Electro Optics, Cleo
2016},
Year = {2016},
Month = {December},
ISBN = {9781943580118},
url = {http://dx.doi.org/10.1364/cleo_at.2016.jw2a.35},
Abstract = {Electron-phonon coupling in graphene is studied across the
Brillouin zone. The contributions from modulated hopping and
conventional deformation potential coupling, and from
intraband and interband coupling are analyzed and related to
available experimental M-point spectroscopy.},
Doi = {10.1364/cleo_at.2016.jw2a.35},
Key = {fds331967}
}
@article{fds331962,
Author = {Gutiérrez, Y and González, F and Saiz, JM and De La Osa Alcaraz and R and Sanz, JM and Ortiz, D and Everitt, HO and Moreno,
F},
Title = {Recent advances in metals for plasmonics applications in the
UV range},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {10351},
Publisher = {SPIE},
Year = {2017},
Month = {January},
ISBN = {9781510611597},
url = {http://dx.doi.org/10.1117/12.2273073},
Abstract = {Plasmonics in the UV-range constitutes a new focus of
research due to new challenges arising in fields such as
biology, chemistry or spectroscopy. Very recent studies
point out gallium and rhodium as good candidates for these
purposes because of their low oxidation tendency and at the
same time, having a good plasmonic response in the UV and
excellent photocatalytic properties. Here we present an
overview of the current state of UV-plasmonics with our
latest findings in the plasmonic activity of materials like
gallium and rhodium.},
Doi = {10.1117/12.2273073},
Key = {fds331962}
}
@article{fds331963,
Author = {Karl, N and Heimbeck, M and Everitt, H and Chen, HT and Taylor, AJ and Benz, A and Reno, JL and Brener, I and Mendis, R and Mittleman,
DM},
Title = {Characterization of switchable terahertz
metasurfaces},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F41-CLEO_SI 2017},
Publisher = {OSA},
Year = {2017},
Month = {January},
ISBN = {9781943580279},
url = {http://dx.doi.org/10.1364/CLEO_SI.2017.SM2J.2},
Abstract = {We perform experimental characterization of switchable THz
metasurfaces using variable-angle broadband THz
ellipsometry. We extract frequency dependent surface
susceptibility tensors and model the applied DC bias as
tuning the conductivity of the active layer.},
Doi = {10.1364/CLEO_SI.2017.SM2J.2},
Key = {fds331963}
}
@article{fds331964,
Author = {Binder, R and Roberts, AT and Kwong, NH and Sandhu, A and Everitt,
HO},
Title = {Nonlinear saddle point spectroscopy and electron-phonon
interaction in graphene},
Pages = {349-386},
Booktitle = {Optical Properties of Graphene},
Publisher = {World Scientific},
Year = {2017},
Month = {January},
ISBN = {9789813148741},
url = {http://dx.doi.org/10.1142/9789813148758_0011},
Abstract = {This chapter focuses on ultrafast nonlinear spectroscopy at
the ultraviolet M- or saddle-point in the electronic
bandstructure of graphene where the position and dynamical
evolution of its absorption peak are especially sensitive to
electron-phonon interactions. Specifically, we explore how
these absorption peak changes are caused by
optically-induced modifications of the phonon temperature by
way of several electron-phonon scattering processes. We
present a detailed theoretical model for electron-phonon
interactions based on the concept of deformation potentials.
We also include a discussion of the phonon dispersion
obtained from dynamical matrices. We derive the electronic
self-energy to lowest order in the electron-phonon
interaction Hamiltonian, then use it to calculate the
interband susceptibility and the differential transmission
spectrum. Using literature values for deformation
potentials, we find good agreement between theory and
experiment, indicating that this formalism provides a good
understanding of the microscopic electron-phonon coupling
processes that renormalize the electronic transitions close
to the M-point and produce the observed differential
transmission spectra.},
Doi = {10.1142/9789813148758_0011},
Key = {fds331964}
}
@article{fds331965,
Author = {Simmons, JG and Reish, ME and Foreman, JV and Liu, J and Everitt,
HO},
Title = {How sulfidation of ZnO powders enhances visible
fluorescence},
Journal = {Journal of Materials Chemistry C},
Volume = {5},
Number = {41},
Pages = {10770-10776},
Publisher = {Royal Society of Chemistry (RSC)},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1039/c7tc04047d},
Abstract = {The mechanism for producing efficient white light phosphors
from sulfidated zinc oxide (ZnO) powders is elucidated. ZnO
powders prepared by vacuum annealing produce powders of
oxygen-deficient ZnO:Zn, while ZnO powders annealed in a
sulfur atmosphere produce a doped ZnO core with a
radially-increasing sulfur concentration gradient capped by
a shell of zinc sulfide (ZnS) domains, ZnO:S/ZnS. As
compared to ZnO:Zn powders, the intensity and quantum
efficiency of the broad, green-tinted white defect
fluorescence more than doubled for the ZnO:S/ZnS powders.
This fluorescence is mediated by certain neutral donor-bound
excitons (DBEs), and it is found that the DBE lifetime and
the rate of energy transfer to the defect emission band
increases for the ZnO:S/ZnS powders. These DBEs are
destroyed by photoexcited free holes, and the hypothesis
that they are removed by the type-II band alignment of the
ZnS cap with the ZnO:S core is confirmed when ZnO:Zn and
ZnO:S/ZnS powders under vacuum are dosed with the hole
scavenger methanol: defect emission increases as the free
hole concentration decreases. The highest ZnO:S/ZnS quantum
efficiency occurs when excited through an impurity band,
also produced by sulfur doping, whose energy coincides with
the light emitting diodes used for commercial solid state
lighting.},
Doi = {10.1039/c7tc04047d},
Key = {fds331965}
}
@article{fds331961,
Author = {Liu, J and Everitt, H},
Title = {Light-driven reaction converts carbon-dioxide into
fuel},
Journal = {Chemical Engineering World},
Volume = {52},
Number = {2},
Pages = {34},
Year = {2017},
Month = {February},
Abstract = {Duke University researchers have developed tiny
nanoparticies that help convert carbon dioxide into methane
using only ultraviolet light as an energy source. In the
past two decades, scientists have explored new and useful
ways that light can be used to add energy to bits of metal
shrunk down to the nanoscale, a field called
plasmonics.},
Key = {fds331961}
}
@article{fds327011,
Author = {Zhu, R and Richard, JT and Brady, DJ and Marks, DL and Everitt,
HO},
Title = {Compressive sensing and adaptive sampling applied to
millimeter wave inverse synthetic aperture
imaging.},
Journal = {Optics Express},
Volume = {25},
Number = {3},
Pages = {2270-2284},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1364/oe.25.002270},
Abstract = {In order to improve speed and efficiency over traditional
scanning methods, a Bayesian compressive sensing algorithm
using adaptive spatial sampling is developed for single
detector millimeter wave synthetic aperture imaging. The
application of this algorithm is compared to random sampling
to demonstrate that the adaptive algorithm converges faster
for simple targets and generates more reliable
reconstructions for complex targets.},
Doi = {10.1364/oe.25.002270},
Key = {fds327011}
}
@article{fds324835,
Author = {Zhang, X and Li, X and Zhang, D and Su, NQ and Yang, W and Everitt, HO and Liu, J},
Title = {Product selectivity in plasmonic photocatalysis for carbon
dioxide hydrogenation},
Journal = {Nature Communications},
Volume = {8},
Pages = {14542},
Publisher = {The Author(s)},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1038/ncomms14542},
Abstract = {Photocatalysis has not found widespread industrial adoption,
in spite of decades of active research, because the
challenges associated with catalyst illumination and
turnover outweigh the touted advantages of replacing heat
with light. A demonstration that light can control product
selectivity in complex chemical reactions could prove to be
transformative. Here, we show how the recently demonstrated
plasmonic behaviour of rhodium nanoparticles profoundly
improves their already excellent catalytic properties by
simultaneously reducing the activation energy and
selectively producing a desired but kinetically unfavourable
product for the important carbon dioxide hydrogenation
reaction. Methane is almost exclusively produced when
rhodium nanoparticles are mildly illuminated as hot
electrons are injected into the anti-bonding orbital of a
critical intermediate, while carbon monoxide and methane are
equally produced without illumination. The reduced
activation energy and super-linear dependence on light
intensity cause the unheated photocatalytic methane
production rate to exceed the thermocatalytic rate at
350 °C.},
Doi = {10.1038/ncomms14542},
Key = {fds324835}
}
@article{fds331960,
Author = {Kong, W and Roberts, AT and Jiao, WY and Fournelle, J and Kim, TH and Losurdo, M and Everitt, HO and Brown, AS},
Title = {UVB-emitting InAlGaN multiple quantum well synthesized using
plasma-assisted molecular beam epitaxy},
Journal = {Aip Advances},
Volume = {7},
Number = {3},
Pages = {035109-035109},
Publisher = {AIP Publishing},
Year = {2017},
Month = {March},
url = {http://dx.doi.org/10.1063/1.4973637},
Abstract = {A high Al-content (y > 0.4) multi-quantum-well (MQW)
structure with a quaternary InxAlyGa(1-x-y)N active layer
was synthesized using plasma-assisted molecular beam
epitaxy. The MQW structure exhibits strong carrier
confinement and room temperature ultraviolet-B (UVB)
photoluminescence an order of magnitude stronger than that
of a reference InxAlyGa(1-x-y)N thin film with comparable
composition and thickness. The samples were characterized
using spectroscopic ellipsometry, atomic force microscopy,
and high-resolution X-ray diffraction. Numerical simulations
suggest that the UVB emission efficiency is limited by
dislocation-related non-radiative recombination centers in
the MQW and at the MQW - buffer interface. Emission
efficiency can be significantly improved by reducing the
dislocation density from 109cm-2 to 107cm-2 and by
optimizing the width and depth of the quantum
wells.},
Doi = {10.1063/1.4973637},
Key = {fds331960}
}
@article{fds342725,
Author = {Li, X and Zhang, X and Everitt, H and Liu, J},
Title = {Using tailored plasmonic photocatalysts for carbon dioxide
hydrogenation},
Journal = {Abstracts of Papers of the American Chemical
Society},
Volume = {253},
Pages = {1 pages},
Publisher = {AMER CHEMICAL SOC},
Year = {2017},
Month = {April},
Key = {fds342725}
}
@article{fds331959,
Author = {Gunawardana, B and Liu, HC and Samaraweera, RL and Heimbeck, MS and Everitt, HO and Iñarrea, J and Reichl, C and Wegscheider, W and Mani,
RG},
Title = {Millimeter wave radiation-induced magnetoresistance
oscillations in the high quality GaAs/AlGaAs 2D electron
system under bichromatic excitation},
Journal = {Physical Review B},
Volume = {95},
Number = {19},
Publisher = {American Physical Society (APS)},
Year = {2017},
Month = {May},
url = {http://dx.doi.org/10.1103/PhysRevB.95.195304},
Abstract = {Millimeter wave radiation-induced magnetoresistance
oscillations are examined in the GaAs/AlGaAs 2D electron
system under bichromatic excitation in order to study the
evolution of the oscillatory diagonal magnetoresistance, Rxx
as the millimeter wave intensity is changed systematically
for various frequency combinations. The results indicate
that at low magnetic fields, the lower frequency millimeter
wave excitation sets the observed Rxx response, as the
higher frequency millimeter wave component determines the
Rxx response at higher magnetic fields. The observations are
qualitatively explained in terms of the order of the
involved transitions. The results are also modeled using the
radiation-driven electron orbit theory.},
Doi = {10.1103/PhysRevB.95.195304},
Key = {fds331959}
}
@article{fds331957,
Author = {Richard, JT and Heimbeck, MS and Blake Autin and L and Everitt,
HO},
Title = {Wide bandwidth, millimeter-resolution inverse synthetic
aperture radar imaging.},
Journal = {Journal of the Optical Society of America
A},
Volume = {34},
Number = {7},
Pages = {1073-1079},
Publisher = {The Optical Society},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1364/josaa.34.001073},
Abstract = {The combination of wide bandwidth W-band inverse synthetic
aperture radar imagery and high-fidelity numerical
simulations has been used to identify distinguishing
signatures from simple metallic and dielectric targets.
Targets are located with millimeter-scale accuracy using
super-resolution techniques. Radon transform reconstructions
of the returns from rotated targets approached the image
quality of the complete data set in a fraction of the time
by sampling as few as 10 angles. The limitations of
shooting-and-bouncing ray simulations at high frequencies
are illustrated through a critical comparison of their
predictions with the measured data and the method of moments
simulations, indicating the importance of accurately
capturing the obfuscating role played by multipath
interference in complex targets.},
Doi = {10.1364/josaa.34.001073},
Key = {fds331957}
}
@article{fds331958,
Author = {Kriisa, A and Liu, HC and Samarweera, RL and Heimbeck, MS and Everitt,
HO and Wegscheider, W and Mani, RG},
Title = {Remotely sensed in microwave irradiated GaAs/AlGaAs
two-dimensional electron system},
Journal = {Journal of Physics: Conference Series},
Volume = {864},
Number = {1},
Pages = {012057-012057},
Publisher = {IOP Publishing},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1088/1742-6596/864/1/012057},
Abstract = {Remotely sensed microwave reflection was measured
concurrently with standard magnetotransport in photo-excited
high mobility GaAs/AlGaAs heterostructure. Experiments
indicate strong reflection resonance on both sides of the
magnetic field axis for linearly polarized
microwave/terahertz photo-excitation over the examined
frequency 30 < f < 330 GHz band. In addition, there is
evidence for electronic heating in the vicinity of cyclotron
resonance (CR), which is indicated by reduced amplitude of
the Shubnikov-de Haas oscillations. Effective mass extracted
from the measurements was found to equal the CR mass within
experimental error.},
Doi = {10.1088/1742-6596/864/1/012057},
Key = {fds331958}
}
@article{fds331956,
Author = {Nasr, M and Richard, JT and Skirlo, SA and Heimbeck, MS and Joannopoulos, JD and Soljacic, M and Everitt, HO and Domash,
L},
Title = {Narrowband Metamaterial Absorber for Terahertz Secure
Labeling},
Journal = {Journal of Infrared, Millimeter, and Terahertz
Waves},
Volume = {38},
Number = {9},
Pages = {1120-1129},
Publisher = {Springer Nature},
Year = {2017},
Month = {September},
url = {http://dx.doi.org/10.1007/s10762-017-0389-7},
Abstract = {Flexible metamaterial films, fabricated by photolithography
on a thin copper-backed polyimide substrate, are used to
mark or barcode objects securely. The films are
characterized by continuous-wave terahertz spectroscopic
ellipsometry and visualized by a scanning confocal imager
coupled to a vector network analyzer that constructed a
terahertz spectral hypercube. These films exhibit a strong,
narrowband, polarization- and angle-insensitive absorption
at wavelengths near 1 mm. Consequently, the films are
nearly indistinguishable at visible or infrared wavelengths
and may be easily observed by terahertz imaging only at the
resonance frequency of the film.},
Doi = {10.1007/s10762-017-0389-7},
Key = {fds331956}
}
@article{fds331955,
Author = {Karl, N and Heimbeck, MS and Everitt, HO and Chen, HT and Taylor, AJ and Benz, A and Reno, JL and Brener, I and Mendis, R and Mittleman,
DM},
Title = {Terahertz phase modulation in a slab waveguide
metasurface},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Publisher = {IEEE},
Year = {2017},
Month = {October},
ISBN = {9781509060481},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2017.8067114},
Abstract = {We describe experimental measurements and simulations of a
switchable THz metasurface device in a slab waveguide
geometry. The device exhibits giant phase modulation of the
TE1 mode at particular frequencies determined by the
metamaterial geometry. Simulations predict that a 2π phase
shift can be realized in an interaction length of only a few
millimeters.},
Doi = {10.1109/IRMMW-THz.2017.8067114},
Key = {fds331955}
}
@article{fds333738,
Author = {Karl, N and Heimbeck, M and Everitt, H and Chen, HT and Taylor, AJ and Benz, A and Reno, JL and Brener, I and Mendis, R and Mittleman,
DM},
Title = {Characterization of switchable terahertz
metasurfaces},
Journal = {2017 Conference on Lasers and Electro Optics, Cleo 2017
Proceedings},
Volume = {2017-January},
Pages = {1-2},
Year = {2017},
Month = {October},
ISBN = {9781943580279},
Abstract = {We perform experimental characterization of switchable THz
metasurfaces using variable-angle broadband THz
ellipsometry. We extract frequency dependent surface
susceptibility tensors and model the applied DC bias as
tuning the conductivity of the active layer.},
Key = {fds333738}
}
@article{fds331966,
Author = {Richard, JT and Everitt, HO},
Title = {Millimeter Wave and Terahertz Synthetic Aperture Radar for
Locating Metallic Scatterers Embedded in Scattering
Media},
Journal = {Ieee Transactions on Terahertz Science and
Technology},
Volume = {7},
Number = {6},
Pages = {732-740},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {November},
url = {http://dx.doi.org/10.1109/TTHZ.2017.2757441},
Abstract = {A rail-mounted synthetic aperture radar has been constructed
to operate at W-band (75-110 GHz) and a terahertz (THz) band
(325-500 GHz) in order to ascertain its ability to detect
and locate isolated small, visually obscured metallic
scatterers embedded in highly scattering dielectric hosts
that are either semitransparent or opaque. A 'top view'
two-dimensional (2-D) algorithm was used to reconstruct
scenes from the acquired data, locating metallic scatterers
at W-band with high-range and cross-range resolution of 4.3
and 16 mm, respectively, improved to 0.86 and 5 mm at the
THz band. Millimeter-sized metallic scatterers were easily
located when embedded in semitransparent, highly scattering
target hosts of polystyrene and polyethylene packing foam
but were more difficult to locate when embedded in
relatively opaque, highly scattering polyisocyanurate
insulation panels. Although the THz band provided the
expected greater spatial resolution, it required the target
to be moved closer to the rail and had a more limited field
of view that prevented some targets from being identified.
Techniques for improving the signal-to-noise ratio are
discussed. This paper establishes a path for developing
techniques to render a complete 3-D reconstruction of a
scene rapidly.},
Doi = {10.1109/TTHZ.2017.2757441},
Key = {fds331966}
}
@article{fds331954,
Author = {Karl, N and Heimbeck, MS and Everitt, HO and Chen, HT and Taylor, AJ and Brener, I and Benz, A and Reno, JL and Mendis, R and Mittleman,
DM},
Title = {Characterization of an active metasurface using terahertz
ellipsometry},
Journal = {Applied Physics Letters},
Volume = {111},
Number = {19},
Pages = {191101-191101},
Publisher = {AIP Publishing},
Year = {2017},
Month = {November},
url = {http://dx.doi.org/10.1063/1.5004194},
Abstract = {Switchable metasurfaces fabricated on a doped epi-layer have
become an important platform for developing techniques to
control terahertz (THz) radiation, as a DC bias can modulate
the transmission characteristics of the metasurface. To
model and understand this performance in new device
configurations accurately, a quantitative understanding of
the bias-dependent surface characteristics is required. We
perform THz variable angle spectroscopic ellipsometry on a
switchable metasurface as a function of DC bias. By
comparing these data with numerical simulations, we extract
a model for the response of the metasurface at any bias
value. Using this model, we predict a giant bias-induced
phase modulation in a guided wave configuration. These
predictions are in qualitative agreement with our
measurements, offering a route to efficient modulation of
THz signals.},
Doi = {10.1063/1.5004194},
Key = {fds331954}
}
@article{fds331953,
Author = {Gutiérrez, Y and Ortiz, D and Saiz, JM and González, F and Everitt,
HO and Moreno, F},
Title = {The UV Plasmonic Behavior of Distorted Rhodium
Nanocubes.},
Journal = {Nanomaterials (Basel, Switzerland)},
Volume = {7},
Number = {12},
Pages = {E425},
Year = {2017},
Month = {December},
url = {http://dx.doi.org/10.3390/nano7120425},
Abstract = {For applications of surface-enhanced spectroscopy and
photocatalysis, the ultraviolet (UV) plasmonic behavior and
charge distribution within rhodium nanocubes is explored by
a detailed numerical analysis. The strongest plasmonic
hot-spots and charge concentrations are located at the
corners and edges of the nanocubes, exactly where they are
the most spectroscopically and catalytically active. Because
intense catalytic activity at corners and edges will reshape
these nanoparticles, distortions of the cubical shape,
including surface concavity, surface convexity, and rounded
corners and edges, are also explored to quantify how
significantly these distortions deteriorate their plasmonic
and photocatalytic properties. The fact that the highest
fields and highest carrier concentrations occur in the
corners and edges of Rh nanocubes (NCs) confirms their
tremendous potential for plasmon-enhanced spectroscopy and
catalysis. It is shown that this opportunity is fortuitously
enhanced by the fact that even higher field and charge
concentrations reside at the interface between the metal
nanoparticle and a dielectric or semiconductor support,
precisely where the most chemically active sites are
located.},
Doi = {10.3390/nano7120425},
Key = {fds331953}
}
@article{fds337337,
Author = {Karl, N and Keiser, GR and Heimbeck, MS and Everitt, HO and Chen, HT and Taylor, AJ and Brener, I and Reno, JL and Mittleman,
DM},
Title = {Linear and nonlinear optics of switchable terahertz
metasurfaces},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F110-Sensors 2018},
Year = {2018},
Month = {January},
ISBN = {9781943580439},
url = {http://dx.doi.org/10.1364/SENSORS.2018.SeW3J.2},
Abstract = {We present experimental studies of the linear and nonlinear
optical response of switchable terahertz metasurfaces, using
terahertz ellipsometry and nonlinear transmission
spectroscopy with intense THz pulses.},
Doi = {10.1364/SENSORS.2018.SeW3J.2},
Key = {fds337337}
}
@article{fds332871,
Author = {Zhang, X and Li, X and Reish, ME and Zhang, D and Su, NQ and Gutiérrez, Y and Moreno, F and Yang, W and Everitt, HO and Liu, J},
Title = {Plasmon-Enhanced Catalysis: Distinguishing Thermal and
Nonthermal Effects.},
Journal = {Nano Letters},
Volume = {18},
Number = {3},
Pages = {1714-1723},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1021/acs.nanolett.7b04776},
Abstract = {In plasmon-enhanced heterogeneous catalysis, illumination
accelerates reaction rates by generating hot carriers and
hot surfaces in the constituent nanostructured metals. In
order to understand how photogenerated carriers enhance the
nonthermal reaction rate, the effects of photothermal
heating and thermal gradients in the catalyst bed must be
confidently and quantitatively characterized. This is a
challenging task considering the conflating effects of light
absorption, heat transport, and reaction energetics. Here,
we introduce a methodology to distinguish the thermal and
nonthermal contributions from plasmon-enhanced catalysts,
demonstrated by illuminated rhodium nanoparticles on oxide
supports to catalyze the CO2 methanation reaction. By
simultaneously measuring the total reaction rate and the
temperature gradient of the catalyst bed, the effective
thermal reaction rate may be extracted. The residual
nonthermal rate of the plasmon-enhanced reaction is found to
grow with a superlinear dependence on illumination
intensity, and its apparent quantum efficiency reaches
∼46% on a Rh/TiO2 catalyst at a surface temperature of 350
°C. Heat and light are shown to work synergistically in
these reactions: the higher the temperature, the higher the
overall nonthermal efficiency in plasmon-enhanced
catalysis.},
Doi = {10.1021/acs.nanolett.7b04776},
Key = {fds332871}
}
@article{fds336442,
Author = {Wang, F and Lee, J and Phillips, DJ and Holliday, SG and Chua, S-L and Bravo-Abad, J and Joannopoulos, JD and Soljačić, M and Johnson, SG and Everitt, HO},
Title = {A high-efficiency regime for gas-phase terahertz
lasers.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {115},
Number = {26},
Pages = {6614-6619},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1073/pnas.1803261115},
Abstract = {We present both an innovative theoretical model and an
experimental validation of a molecular gas optically pumped
far-infrared (OPFIR) laser at 0.25 THz that exhibits 10×
greater efficiency (39% of the Manley-Rowe limit) and
1,000× smaller volume than comparable commercial lasers.
Unlike previous OPFIR-laser models involving only a few
energy levels that failed even qualitatively to match
experiments at high pressures, our ab initio theory matches
experiments quantitatively, within experimental
uncertainties with no free parameters, by accurately
capturing the interplay of millions of degrees of freedom in
the laser. We show that previous OPFIR lasers were
inefficient simply by being too large and that high powers
favor high pressures and small cavities. We believe that
these results will revive interest in OPFIR laser as a
powerful and compact source of terahertz
radiation.},
Doi = {10.1073/pnas.1803261115},
Key = {fds336442}
}
@article{fds336443,
Author = {Swearer, DF and Gottheim, S and Simmons, JG and Phillips, DJ and Kale,
MJ and McClain, MJ and Christopher, P and Halas, NJ and Everitt,
HO},
Title = {Monitoring Chemical Reactions with Terahertz Rotational
Spectroscopy},
Journal = {Acs Photonics},
Volume = {5},
Number = {8},
Pages = {3097-3106},
Publisher = {American Chemical Society (ACS)},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1021/acsphotonics.8b00342},
Abstract = {Rotational spectroscopy is introduced as a new in situ
method for monitoring gas-phase reactants and products
during chemical reactions. Exploiting its unambiguous
molecular recognition specificity and extraordinary
detection sensitivity, rotational spectroscopy at terahertz
frequencies was used to monitor the decomposition of
carbonyl sulfide (OCS) over an aluminum nanocrystal (AlNC)
plasmonic photocatalyst. The intrinsic surface oxide on
AlNCs is discovered to have a large number of strongly basic
sites that are effective for mediating OCS decomposition.
Spectroscopic monitoring revealed two different photothermal
decomposition pathways for OCS, depending on the absence or
presence of H2O. The strength of rotational spectroscopy is
witnessed through its ability to detect and distinguish
isotopologues of the same mass from an unlabeled OCS
precursor at concentrations of <1 nanomolar or partial
pressures of <10 μTorr. These attributes recommend
rotational spectroscopy as a compelling alternative for
monitoring gas-phase chemical reactants and products in real
time.},
Doi = {10.1021/acsphotonics.8b00342},
Key = {fds336443}
}
@article{fds362903,
Author = {Zhang, X and Li, L and Yang, W and Everitt, H and Liu,
J},
Title = {Thermal and light effect in plasmonic catalysis},
Journal = {Abstracts of Papers of the American Chemical
Society},
Volume = {256},
Pages = {1 pages},
Publisher = {AMER CHEMICAL SOC},
Year = {2018},
Month = {August},
Key = {fds362903}
}
@article{fds346702,
Author = {Gutiérrez, Y and Losurdo, M and García-Fernández, P and De La
Maza and MS and González, F and Brown, AS and Everitt, HO and Junquera, J and Moreno, F},
Title = {Dielectric function and plasmonic behavior of Ga(II) and
Ga(III)},
Journal = {Optical Materials Express},
Volume = {9},
Number = {10},
Pages = {4050-4060},
Publisher = {The Optical Society},
Year = {2019},
Month = {January},
url = {http://dx.doi.org/10.1364/OME.9.004050},
Abstract = {In order to exploit gallium's (Ga) rich polymorphism in the
design of phase-change plasmonic systems, accurate
understanding of the dielectric function of the different
Ga-phases is crucial. The dielectric dispersion profiles of
those phases appearing at atmospheric pressure have been
reported in the literature, but there is no information on
the dielectric function of the high-pressure Ga-phases.
Through first principles calculations we present a
comprehensive analysis of the interdependence of the crystal
structure, band structure, and dielectric function of two
high-pressure Ga phases (Ga(II) and Ga(III)). The plasmonic
behavior of these high-pressure Ga-phases is compared to
those stable (liquid- and α-Ga) and metastable (β-,γ- and
δ-Ga) at atmospherics pressure. This analysis can have
important implications in the design of pressuredriven
phase-change Ga plasmonic devices and high-pressure SERS
substrates.},
Doi = {10.1364/OME.9.004050},
Key = {fds346702}
}
@article{fds341503,
Author = {Kriisa, A and Samaraweera, RL and Heimbeck, MS and Everitt, HO and Reichl, C and Wegscheider, W and Mani, RG},
Title = {Cyclotron resonance in the high mobility GaAs/AlGaAs 2D
electron system over the microwave, mm-wave, and terahertz-
bands.},
Journal = {Scientific Reports},
Volume = {9},
Number = {1},
Pages = {2409},
Year = {2019},
Month = {February},
url = {http://dx.doi.org/10.1038/s41598-019-39186-2},
Abstract = {The reflected microwave power from the photo-excited high
mobility GaAs/AlGaAs 2D device has been measured over the
wide frequency band spanning from 30 to 330 GHz
simultaneously along with diagonal magnetoresistance as a
function of the magnetic field. Easily distinguishable
resonances in the reflected power signal are observed at the
same magnetic fields as a reduced amplitude in the
Shubnikov-de Haas (SdH) oscillations of the diagonal
magnetoresistance. The reflection resonances with concurrent
amplitude reduction in SdH oscillations are correlated with
cyclotron resonance induced by microwave, mm-wave, and
terahertz photoexcitation. The magnetoplasma effect was also
investigated. The results suggest a finite frequency
zero-magnetic-field intercept, providing an estimate for the
plasma frequency. The experimentally measured plasma
frequency appears to be somewhat lower than the estimated
plasma frequency for these Hall bars. The results, in sum,
are consistent with an effective mass ratio of
m*/m = 0.067, the standard value, even in these high
mobility GaAs/AlGaAs devices, at very large filling factors.
Preliminary findings from this article have been published
as conference proceedings, see Kriisa, A., et al., J. of
Phys. Conf. Ser. 864, 012057 (2017).},
Doi = {10.1038/s41598-019-39186-2},
Key = {fds341503}
}
@article{fds341336,
Author = {Li, X and Zhang, X and Everitt, HO and Liu, J},
Title = {Light-Induced Thermal Gradients in Ruthenium Catalysts
Significantly Enhance Ammonia Production.},
Journal = {Nano Letters},
Volume = {19},
Number = {3},
Pages = {1706-1711},
Year = {2019},
Month = {March},
url = {http://dx.doi.org/10.1021/acs.nanolett.8b04706},
Abstract = {Industrial scale catalytic chemical synthesis demands both
high reaction rates and high product yields. In exothermic
chemical reactions, these conflicting objectives require a
complex balance of optimized catalysts, high temperatures,
high pressures, and multiple recycling steps, as in the
energy-intensive Haber-Bosch process for ammonia synthesis.
Here we report that illumination of a conventional
ruthenium-based catalyst produces ammonia with high reaction
rates and high conversion yields. Indeed, using continuous
wave light-emitting diodes that simulate concentrated solar
illumination, ammonia is copiously produced without any
external heating or elevated pressures. The possibility of
nonthermal plasmonic effects are excluded by carefully
comparing the catalytic activity under direct and indirect
illumination. Instead, thermal gradients, created and
controlled by photothermal heating of the illuminated
catalyst surface, are shown to be responsible for the high
reaction rates and conversion yields. This nonisothermal
environment enhances both by balancing the conflicting
requirements of kinetics and thermodynamics, heralding the
use of optically controlled thermal gradients as a
universal, scalable strategy for the catalysis of many
exothermic chemical reactions.},
Doi = {10.1021/acs.nanolett.8b04706},
Key = {fds341336}
}
@article{fds343597,
Author = {Lou, M and Swearer, DF and Gottheim, S and Phillips, DJ and Simmons, JG and Halas, NJ and Everitt, HO},
Title = {Quantitative analysis of gas phase molecular constituents
using frequency-modulated rotational spectroscopy.},
Journal = {Review of Scientific Instruments},
Volume = {90},
Number = {5},
Pages = {053110},
Year = {2019},
Month = {May},
url = {http://dx.doi.org/10.1063/1.5093912},
Abstract = {Rotational spectroscopy has been used for decades for
virtually unambiguous identification of gas phase molecular
species, but it has rarely been used for the quantitative
analysis of molecular concentrations. Challenges have
included the nontrivial reconstruction of integrated line
strengths from modulated spectra, the correlation of
pressure-dependent line shape and strength with partial
pressure, and the multiple standing wave interferences and
modulation-induced line shape asymmetries that sensitively
depend on source-chamber-detector alignment. Here, we
introduce a quantitative analysis methodology that overcomes
these challenges, reproducibly and accurately recovering gas
molecule concentrations using a calibration procedure with a
reference gas and a conversion based on calculated line
strengths. The technique uses frequency-modulated rotational
spectroscopy and recovers the integrated line strength from
a Voigt line shape that spans the Doppler- and
pressure-broadened regimes. Gas concentrations were
accurately quantified to within the experimental error over
more than three orders of magnitude, as confirmed by the
cross calibration between CO and N<sub>2</sub>O and by the
accurate recovery of the natural abundances of four
N<sub>2</sub>O isotopologues. With this methodology,
concentrations of hundreds of molecular species may be
quantitatively measured down to the femtomolar regime using
only a single calibration curve and the readily available
libraries of calculated integrated line strengths,
demonstrating the power of this technique for the
quantitative gas-phase detection, identification, and
quantification.},
Doi = {10.1063/1.5093912},
Key = {fds343597}
}
@article{fds341504,
Author = {Everitt, HO and Tyler, T and Caraway, BD and Bingham, CM and Llopis, A and Heimbeck, MS and Padilla, WJ and Smith, DR and Jokerst,
NM},
Title = {Strain Sensing with Metamaterial Composites},
Journal = {Advanced Optical Materials},
Volume = {7},
Number = {9},
Year = {2019},
Month = {May},
url = {http://dx.doi.org/10.1002/adom.201801397},
Abstract = {Mapping strain fields in visually opaque structural
composites—for which failure is often sudden, irreparable,
and even catastrophic—requires techniques to locate and
record regions of stress, fatigue, and incipient failure.
Many composite materials are transparent in the terahertz
spectral region, but their strain history is often too
subtle to recover. Here, terahertz metamaterials with
strain-severable junctions are introduced that can identify
structurally compromised regions of composite materials.
Specifically, multilayer arrays of aluminum meta-atoms are
designed and fabricated as strip dipole antennas with a
terahertz frequency resonance and a strong response to
cross-polarized radiation that disappears when local stress
irreversibly breaks their bowtie-shaped junction. By
spatially mapping the local polarimetric response of this
metamaterial as a function of global strain, the regions of
local stress extrema experienced by a visually opaque
material may be visualized. This proof-of-concept
demonstration heralds the opportunity for embedding
metamaterial laminates within composites to record and
recover their strain-dependent history of
fatigue.},
Doi = {10.1002/adom.201801397},
Key = {fds341504}
}
@article{fds345428,
Author = {Swearer, DF and Knowles, NR and Everitt, HO and Halas,
NJ},
Title = {Light-Driven Chemical Looping for Ammonia
Synthesis},
Journal = {Acs Energy Letters},
Volume = {4},
Number = {7},
Pages = {1505-1512},
Year = {2019},
Month = {May},
url = {http://dx.doi.org/10.1021/acsenergylett.9b00860},
Abstract = {Synthetic ammonia has been the primary worldwide source of
agricultural fertilizer over the last century and is a
promising carbon-free energy carrier for sustainable
transportation. Despite its global importance, synthetic
ammonia produced with the Haber-Bosch process is extremely
energy- and resource-intensive. Here we demonstrate a
three-step chemical looping strategy to produce ammonia
using only light, natural gas, nitrogen, and water. Titanium
nitride nanoparticles were utilized as plasmonic antennas to
assist the transformation of magnesium-based nanomaterials
through oxide, metallic, and nitride phases under optical
illumination. All reactions were performed and monitored in
situ using frequency-modulated rotational spectroscopy,
which allowed the experiments to take advantage of the
rotational spectra's unique sensitivity to isotopic labeling
to monitor and verify key reaction intermediates. This
validation of a light-driven process for the synthesis of
ammonia demonstrates an innovative route toward
photosynthetic production of essential chemical
commodities.},
Doi = {10.1021/acsenergylett.9b00860},
Key = {fds345428}
}
@article{fds342476,
Author = {Mohanta, A and Simmons, JG and Shen, G and Kim, SM and Kung, P and Everitt,
HO},
Title = {Al doping in ZnO nanowires enhances ultraviolet emission and
suppresses broad defect emission},
Journal = {Journal of Luminescence},
Volume = {211},
Pages = {264-270},
Year = {2019},
Month = {July},
url = {http://dx.doi.org/10.1016/j.jlumin.2019.03.049},
Abstract = {The effect of Al doping on the nature of ultraviolet (UV)
near band edge emission and broadband “green” visible
emission from deep defects in ZnO nanowires is explored by
temperature- and excitation intensity-dependent
photoluminescence (PL) spectroscopy. Unlike comparably
fabricated undoped ZnO nanowires, whose PL spectra is
dominated by green emission from oxygen vacancies and whose
UV emission broadens and redshifts with increasing
excitation intensity, Al-doped ZnO nanowires grown by
chemical vapor deposition are smaller and have PL spectra
dominated by UV emission that neither broadens nor redshifts
significantly with increasing excitation intensity. The
excitation intensity-dependent manner in which Al doping
enhances UV emission at the expense of green emission
indicates that the doping process creates many new donor
sites that prevent excitons localized there from activating
these green emitting defects.},
Doi = {10.1016/j.jlumin.2019.03.049},
Key = {fds342476}
}
@article{fds339639,
Author = {Roberts, AT and Yang, J and Reish, ME and Alabastri, A and Halas, NJ and Nordlander, P and Everitt, HO},
Title = {Plasmonic nanoparticle-based epoxy photocuring: A deeper
look},
Journal = {Materials Today},
Volume = {27},
Pages = {14-20},
Publisher = {Elsevier BV},
Year = {2019},
Month = {July},
url = {http://dx.doi.org/10.1016/j.mattod.2018.09.005},
Abstract = {Many epoxy adhesives require high temperatures to bond
composite materials. However, oven heating severely
restricts what may be attached or enclosed within composite
material-based structures and greatly limits the
possibilities for repair. Inspired by initial reports of
photothermal epoxy curing using plasmonic nanoparticles, we
examine how laser-illuminated Au nanoparticles embedded
within high-temperature epoxy films convert the conventional
thermal curing process into a photothermally driven one. Our
theoretical investigations reveal that plasmonic
nanoparticle-based epoxy photocuring proceeds through a
four-stage process: a rapid, plasmon-induced temperature
increase, a slow localized initialization of the curing
chemistry that increases the optical absorption of the epoxy
film, a subsequent temperature increase as the epoxy absorbs
the laser radiation directly, and a final stage that
completes the chemical transformation of the epoxy film to
its cured state. Our experimental studies validate this
model, and also reveal that highly local photocuring can
create a stronger bond between composite materials than
thermal curing without nanoparticles, at times even stronger
than the composite material itself, substantially reducing
the time needed for the curing process. Our findings support
key advances in our understanding of this approach to the
rapid, highly efficient bonding and repair of composite
materials.},
Doi = {10.1016/j.mattod.2018.09.005},
Key = {fds339639}
}
@article{fds343342,
Author = {Gutiérrez, Y and Losurdo, M and García-Fernández, P and Sainz de
la Maza, M and González, F and Brown, AS and Everitt, HO and Junquera,
J and Moreno, F},
Title = {Gallium Polymorphs: Phase-Dependent Plasmonics},
Journal = {Advanced Optical Materials},
Volume = {7},
Number = {13},
Year = {2019},
Month = {July},
url = {http://dx.doi.org/10.1002/adom.201900307},
Abstract = {Interest in gallium (Ga) is growing rapidly, thanks in part
to its wide spectral tunability and its intriguing
temperature-dependent polymorphism. In order to exploit and
control phase-change plasmonics in the liquid and solid
phases of Ga, an accurate understanding of the dielectric
functions for each Ga phase is needed. A comprehensive
analysis of the interdependence of the crystal structure,
band structure, and dielectric function of the several Ga
phases (liquid, α, β, γ, δ) is presented, showing that
the selective presence of flat bands in the vicinity of the
Fermi energy is crucial to understand the metallicity of
each phase. The dielectric function obtained through first
principles calculations is compared with experimental
measurements obtained by spectroscopic ellipsometry. Cooling
liquid Ga always produces a mixture of phases, and how the
volume fraction of each phase may be deduced from these pure
phase dielectric functions and an analysis of the measured
spectra using a Bruggeman effective medium approximation is
demonstrated. Figures of merit are presented, and
applications of Ga polymorphism are discussed for
propagating and localized surface plasmon resonances in Ga
thin films and nanostructures, respectively. This research
can have important implications on the phase change control
for plasmonics/photonic applications with
gallium.},
Doi = {10.1002/adom.201900307},
Key = {fds343342}
}
@article{fds344624,
Author = {Li, X and Everitt, HO and Liu, J},
Title = {Confirming nonthermal plasmonic effects enhance
CO2 methanation on Rh/TiO2
catalysts},
Journal = {Nano Research},
Volume = {12},
Number = {8},
Pages = {1906-1911},
Year = {2019},
Month = {August},
url = {http://dx.doi.org/10.1007/s12274-019-2457-x},
Abstract = {In some cases, illumination of traditional thermal catalysts
and tailored plasmonic photocatalysts may synergistically
combine thermal and nonthermal mechanisms to enhance
reaction rates and improve product selectivity at reduced
temperatures. To understand how these attributes are
achieved in plasmon-driven catalysis, these intertwined
thermal and nonthermal effects must be untangled. Here, we
show how a novel indirect illumination technique, in
conjunction with precisely monitored thermal profiles of the
catalyst, can confirm and clarify the role of nonthermal
effects in plasmon-enhanced carbon dioxide methanation on a
Rh/TiO2 photocatalyst. We find that the extracted nonthermal
methane production rate has a linear dependence on the top
surface temperature, distinctly different from an
exponential dependence for thermal catalysis. We also find
that the apparent quantum efficiency from the nonthermal
contribution has no dependence on light intensity but
maintains a linear dependence on top surface temperatures
between 200 and 350 °C. The clear exposition of nonthermal
effects in the Rh/TiO2 plasmonic photocatalyst illustrates
how this methodology may be applied for the quantitative
evaluation of thermal and nonthermal light effects in other
plasmon-enhanced catalytic reactions.[Figure not available:
see fulltext.].},
Doi = {10.1007/s12274-019-2457-x},
Key = {fds344624}
}
@article{fds347027,
Author = {Chevalier, P and Amirzhan, A and Wang, F and Piccardo, M and Johnson,
SG and Capasso, F and Everitt, HO},
Title = {Widely tunable compact terahertz gas lasers.},
Journal = {Science (New York, N.Y.)},
Volume = {366},
Number = {6467},
Pages = {856-860},
Year = {2019},
Month = {November},
url = {http://dx.doi.org/10.1126/science.aay8683},
Abstract = {The terahertz region of the electromagnetic spectrum has
been the least utilized owing to inadequacies of available
sources. We introduce a compact, widely frequency-tunable,
extremely bright source of terahertz radiation: a gas-phase
molecular laser based on rotational population inversions
optically pumped by a quantum cascade laser. By identifying
the essential parameters that determine the suitability of a
molecule for a terahertz laser, almost any rotational
transition of almost any molecular gas can be made to lase.
Nitrous oxide is used to illustrate the broad tunability
over 37 lines spanning 0.251 to 0.955 terahertz, each with
kilohertz linewidths. Our analysis shows that laser lines
spanning more than 1 terahertz with powers greater than 1
milliwatt are possible from many molecular gases pumped by
quantum cascade lasers.},
Doi = {10.1126/science.aay8683},
Key = {fds347027}
}
@article{fds345884,
Author = {Abed Zadeh and A and Barés, J and Brzinski, TA and Daniels, KE and Dijksman, J and Docquier, N and Everitt, HO and Kollmer, JE and Lantsoght, O and Wang, D and Workamp, M and Zhao, Y and Zheng,
H},
Title = {Enlightening force chains: a review of photoelasticimetry in
granular matter},
Journal = {Granular Matter},
Volume = {21},
Number = {4},
Year = {2019},
Month = {November},
url = {http://dx.doi.org/10.1007/s10035-019-0942-2},
Abstract = {A photoelastic material will reveal its internal stresses
when observed through polarizing filters. This eye-catching
property has enlightened our understanding of granular
materials for over half a century, whether in the service of
art, education, or scientific research. In this review
article in honor of Robert Behringer, we highlight both his
pioneering use of the method in physics research, and its
reach into the public sphere through museum exhibits and
outreach programs. We aim to provide clear protocols for
artists, exhibit-designers, educators, and scientists to use
in their own endeavors. It is our hope that this will build
awareness about the ubiquitous presence of granular matter
in our lives, enlighten its puzzling behavior, and promote
conversations about its importance in environmental and
industrial contexts. To aid in this endeavor, this paper
also serves as a front door to a detailed wiki containing
open, community-curated guidance on putting these methods
into practice (Abed-Zadeh et al. in Photoelastic methods
wiki https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/home,
2019).},
Doi = {10.1007/s10035-019-0942-2},
Key = {fds345884}
}
@article{fds359885,
Author = {Khatib, O and Tyler, T and Padilla, WJ and Jokerst, NM and Everitt,
HO},
Title = {Strain sensing with THz metamaterial composites},
Journal = {Optics Infobase Conference Papers},
Year = {2020},
Month = {January},
ISBN = {9781557528209},
Abstract = {Terahertz metamaterials with strain-sensitive junctions are
introduced to identify structurally compromised regions of
composite materials. Spatially mapping the local
polarimetric metamaterial response visualizes and records
regions of stress extrema experienced by visibly opaque
materials.},
Key = {fds359885}
}
@article{fds359886,
Author = {Thul, D and Bernath, R and Fairchild, SR and Richardson, M and Everitt,
H},
Title = {Infrared/THz double resonance spectroscopy at atmospheric
pressure},
Journal = {Optics Infobase Conference Papers},
Year = {2020},
Month = {January},
ISBN = {9781557528209},
Abstract = {Double resonant spectroscopy measurements are presented
using a tunable 9-11 μm pump source with a sub-nanosecond
pulse train output. This method is demonstrated at
atmospheric pressure for methyl halides using a THz
probe.},
Key = {fds359886}
}
@article{fds359887,
Author = {Chevalier, P and Amirzhan, A and Wang, F and Piccardo, M and Johnson,
SG and Capasso, F and Everitt, HO},
Title = {Tunable quantum-cascade laser pumped molecular lasers for
terahertz imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2020},
Month = {January},
ISBN = {9781557528209},
Abstract = {We demonstrate a new class of optically pumped far-infrared
lasers using quantum cascade lasers as the pump. Following
an initial demonstration using nitrous oxide, we show how we
can generate light at THz frequencies using different
gases.},
Key = {fds359887}
}
@article{fds359888,
Author = {Thul, D and Bernath, R and Fairchild, SR and Richardson, M and Everitt,
H},
Title = {Atmospheric propagation of sub-picosecond pulses at 10
μm},
Journal = {Optics Infobase Conference Papers},
Year = {2020},
Month = {January},
ISBN = {9781557528209},
Abstract = {This work presents the design and performance of a 10 μm
sub-picosecond laser source. Initial measurements of
high-intensity atmospheric propagation are also presented,
which represent the first kilometer-range studies of
ultrashort pulses in this wavelength regime.},
Key = {fds359888}
}
@article{fds352992,
Author = {Gutiérrez, Y and González, F and Saiz, JM and Alcaraz De La Osa and R and Albella, P and Ortiz, D and Everitt, HO and Moreno,
F},
Title = {Metals and dielectrics for UV plasmonics},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {11345},
Year = {2020},
Month = {January},
ISBN = {9781510634626},
url = {http://dx.doi.org/10.1117/12.2555740},
Abstract = {An overview on our latest research on UV plasmonics with Rh
and Ga metal nanostructures is presented. We will pay
attention to their plasmonic performance and UV tunability.
For Ga, its polymorphism will be analyzed and for Rh three
characteristic geometries will be studied: tripod star,
nanocube and tetrahedron. As an alternative to metals, low
heat generation materials for bio applications will be
analyzed. A numerical analysis of several candidate low loss
dielectric materials that show HRI properties in the UV will
be presented. In particular, this analysis will focus on the
near-field enhancement and scattering directionality above 3
eV.},
Doi = {10.1117/12.2555740},
Key = {fds352992}
}
@article{fds353054,
Author = {Amirzhan, A and Chevalier, P and Wang, F and Piccardo, M and Johnson,
SG and Everitt, HO and Capasso, F},
Title = {Room temperature compact terahertz laser tunable over 1
THz},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F183-CLEO-SI 2020},
Year = {2020},
Month = {January},
ISBN = {9781943580767},
url = {http://dx.doi.org/10.1364/CLEO_SI.2020.STu3G.1},
Abstract = {We demonstrate a new type of Terahertz Gas Laser pumped by a
tunable solid-state laser. This laser has a wide tuning
range and operates at room temperature with a high
efficiency in a very compact design.},
Doi = {10.1364/CLEO_SI.2020.STu3G.1},
Key = {fds353054}
}
@article{fds349336,
Author = {Heimbeck, MS and Everitt, HO},
Title = {Terahertz digital holographic imaging},
Journal = {Advances in Optics and Photonics},
Volume = {12},
Number = {1},
Pages = {1-59},
Publisher = {The Optical Society},
Year = {2020},
Month = {March},
url = {http://dx.doi.org/10.1364/AOP.12.000001},
Abstract = {This tutorial describes the application of digital
holography to the terahertz spectral region and demonstrates
how to reconstruct images of complex dielectric targets.
Using highly coherent terahertz sources, high-fidelity
amplitude and phase reconstructions are achieved, but
because the millimeter-scale wavelengths approach the
decimeter-sized targets and optical components, undesirable
aperture diffraction degrades the quality of the
reconstructions. Consequently, off-axis terahertz digital
holography differs significantly from its visible light
counterpart. This tutorial addresses these challenges within
the angular spectrum method and the Fresnel approximation
for digital hologram reconstruction, from which the
longitudinal and transverse resolution limits may be
specified. We observed longitudinal resolution (λ∕284)
almost two times better than has been achieved with visible
light digital holographic microscopy and demonstrate that
submicrometer longitudinal resolution is possible using
millimeter wavelengths for an imager limited ultimately by
the phase stability of the terahertz source and/or receiver.
Minimizing the number of optical components, using only
large reflective optics, maximizing the angle of the
off-axis reference beam, and judicious selection of spatial
frequency filters all contribute to improve the quality of
the reconstructed image. As in visible wavelength analog
holography, the observed transverse resolution in terahertz
digital holography is comparable to the wavelength but
improves for features near the edge of the imaged object
compared with features near the center, a behavior
characterized by a modified description of the holographic
transfer function introduced here. Holograms were recorded
by raster scanning a sensitive superheterodyne receiver, and
several visibly transparent and opaque dielectric structures
were quantitatively examined to demonstrate the compelling
application of terahertz digital holography for
nondestruc-tive test, evaluation, and analysis.},
Doi = {10.1364/AOP.12.000001},
Key = {fds349336}
}
@article{fds349539,
Author = {Gutiérrez, Y and Losurdo, M and González, F and Everitt, HO and Moreno, F},
Title = {Nanoplasmonic Photothermal Heating and Near-Field
Enhancements: A Comparative Survey of 19
Metals},
Journal = {The Journal of Physical Chemistry C},
Volume = {124},
Number = {13},
Pages = {7386-7395},
Year = {2020},
Month = {April},
url = {http://dx.doi.org/10.1021/acs.jpcc.0c00757},
Abstract = {Localized surface plasmon resonances optically excited in
metallic nanoparticles (NPs) produce beneficial thermal and
nonthermal effects. Nonthermal effects, such as enhancing
and localizing fields on subwavelength scales and
photo-generating hot carriers, have been extensively
exploited, while interest in highly localized photothermal
heating is reviving. Both effects may work together
synergistically, such as increasing the efficiency of a
photocatalytic process, or they may work against each other,
such as accelerating the desorption of analytes in
surface-enhanced spectroscopy. To compare how these effects
depend on the composition and size of the NP, we report a
quantitative survey of thermal and nonthermal properties in
the visible-solar (1.7-4.1 eV) and ultraviolet (3.1-6.2 eV)
ranges for 19 metals, including conventional plasmonic
materials (gold, silver, copper), an alkaline earth metal
(magnesium), post-transition metals (aluminum, gallium,
indium), and a wide variety of transition metals. Figures of
merit that reflect the resistive losses and electric field
enhancement factor of the NPs were used in this comparative
analysis.},
Doi = {10.1021/acs.jpcc.0c00757},
Key = {fds349539}
}
@article{fds349389,
Author = {Li, X and Everitt, HO and Liu, J},
Title = {Synergy between thermal and nonthermal effects in plasmonic
photocatalysis},
Journal = {Nano Research},
Volume = {13},
Number = {5},
Pages = {1268-1280},
Year = {2020},
Month = {May},
url = {http://dx.doi.org/10.1007/s12274-020-2694-z},
Abstract = {Plasmonic photocatalysis represents the synergetic union of
two active fields of research: plasmonic effects in
illuminated metallic nanoparticles and catalytic effects in
tailored metallic nanoparticles. Traditionally, metallic
nanoparticles that excel for one application are limited for
the other, but recent developments have shown that desirable
catalytic behaviors, such as reduced activation barriers and
improved product selectivity, derive from nonthermal
behaviors uniquely produced by this synergy. After examining
such findings, this review will address a specific debate
that has recently surfaced: what is the relative degree of
contributions of thermal and nonthermal effects in plasmonic
photocatalysis? We demonstrate the importance of correctly
accounting for thermal effects before characterizing
nonthermal contributions. We show that another synergy
occurs: these desirable nonthermal behaviors have a
temperature dependence, and the resulting
temperature-dependent reaction rates far exceed what can be
explained from purely thermal effects alone. Thus, the
synergy of plasmonic photocatalysis offers an exciting new
contribution to the quest for efficient, selective,
sustainable methods for chemical synthesis and energy
conversion. [Figure not available: see fulltext.].},
Doi = {10.1007/s12274-020-2694-z},
Key = {fds349389}
}
@article{fds352644,
Author = {Amirzhan, A and Chevalier, P and Wang, F and Piccardo, M and Johnson,
SG and Everitt, HO and Capasso, F},
Title = {Room Temperature Compact Terahertz Laser Tunable over 1
THz},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Volume = {2020-May},
Year = {2020},
Month = {May},
ISBN = {9781943580767},
Abstract = {We demonstrate a new type of Terahertz Gas Laser pumped by a
tunable solid-state laser. This laser has a wide tuning
range and operates at room temperature with a high
efficiency in a very compact design.},
Key = {fds352644}
}
@article{fds353324,
Author = {H. Everitt},
Title = {Erratum for the Report: "Widely tunable compact terahertz
gas lasers" by P. Chevalier, A. Amirzhan, F. Wang, M.
Piccardo, S. G. Johnson, F. Capasso, H. O.
Everitt.},
Journal = {Science (New York, N.Y.)},
Volume = {368},
Number = {6491},
Pages = {eabc5418},
Year = {2020},
Month = {May},
url = {http://dx.doi.org/10.1126/science.abc5418},
Doi = {10.1126/science.abc5418},
Key = {fds353324}
}
@article{fds356453,
Author = {Kuhs, CT and Jacobson, CR and Simmons, JG and Halas, NJ and Everitt,
HO},
Title = {Can thermal annealing of ZnO and ZnS powders produce Type-II
heterostructures?},
Journal = {Optics Infobase Conference Papers},
Year = {2020},
Month = {September},
ISBN = {9781943580804},
url = {http://dx.doi.org/10.1364/FIO.2020.JW6A.13},
Abstract = {Charge separation in ZnO/ZnS type II heterostructures may
prove useful as a photocatalyst support. This work used
cathodoluminescence spectroscopy to explore whether thermal
annealing of ZnO and ZnS powders can synthesize such
heterostructures.},
Doi = {10.1364/FIO.2020.JW6A.13},
Key = {fds356453}
}
@article{fds355818,
Author = {Khatib, O and Tyler, T and Padilla, WJ and Jokerst, NM and Everitt,
HO},
Title = {Strain Mapping with THz Metamaterial Composites},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Volume = {2020-November},
Pages = {317},
Year = {2020},
Month = {November},
ISBN = {9781728166209},
url = {http://dx.doi.org/10.1109/IRMMW-THz46771.2020.9370546},
Abstract = {Terahertz metamaterials with strain-sensitive junctions are
introduced to identify structurally compromised regions of
composite materials. Spatially mapping the local
polarimetric metamaterial response visualizes and records
regions of stress extrema experienced by visibly opaque
materials.},
Doi = {10.1109/IRMMW-THz46771.2020.9370546},
Key = {fds355818}
}
@article{fds360656,
Author = {Reyes, D and Schneiderman, M and Thul, D and Bernath, R and Richardson,
M and Everitt, H},
Title = {LWIR-THz double resonance spectroscopy for remote
identification of trace gases},
Journal = {Optics Infobase Conference Papers},
Year = {2021},
Month = {January},
ISBN = {9781557528209},
Abstract = {In preparation for remote atmospheric detection, preliminary
double resonance spectroscopic measurements were made of
CH3Cl and CH3F using a LWIR pump to excite transient
vibrational states and a THz source to probe the rotational
levels.},
Key = {fds360656}
}
@article{fds360657,
Author = {Chevalier, P and Amirzhan, A and Rowlette, J and Stinson, T and Pushkarsky, M and Day, T and Capasso, F and Everitt,
HO},
Title = {Widely tunable quantum cascade laser-pumped methyl fluoride
terahertz laser},
Journal = {Optics Infobase Conference Papers},
Year = {2021},
Month = {January},
ISBN = {9781557528209},
Abstract = {We demonstrate and characterize a new quantum cascade
laser-pumped molecular laser using methyl fluoride as its
gain medium. We show that a laser using this gain medium can
exhibit a low pump threshold while allowing emission over
more than 100 lines spanning from 300 GHz up to 1.3
THz.},
Key = {fds360657}
}
@article{fds360562,
Author = {Khatib, O and Tyler, T and Padilla, WJ and Jokerst, NM and Everitt,
HO},
Title = {Strain mapping with THz metamaterial composites},
Journal = {Optics Infobase Conference Papers},
Year = {2021},
Month = {January},
ISBN = {9781557528209},
Abstract = {Terahertz metamaterials that exhibit broad spectral
resonances are used to probe local strain fields. By
choosing specific frequencies and polarizations for
measurement, it is possible to obtain unique spatial maps
for different strain states.},
Key = {fds360562}
}
@article{fds360076,
Author = {Chevalier, P and Amirzhan, A and Rowlette, J and Stinson, T and Pushkarsky, M and Day, T and Everitt, HO and Capasso,
F},
Title = {Compact, low threshold methyl fluoride terahertz laser
pumped by a quantum cascade laser},
Journal = {Optics Infobase Conference Papers},
Year = {2021},
Month = {January},
ISBN = {9781557528209},
Abstract = {We demonstrate a quantum cascade laser-pumped terahertz
laser using methyl fluoride gas. The large dipole moment of
this molecule allows for a low threshold laser with
frequency tunable emission spanning more than one
terahertz.},
Key = {fds360076}
}
@article{fds370615,
Author = {Li, X and Liu, J and Everitt, HO},
Title = {Untangling Thermal and Nonthermal Effects in Plasmonic
Photocatalysis},
Pages = {191-230},
Booktitle = {Plasmonic Catalysis: From Fundamentals to
Applications},
Year = {2021},
Month = {January},
ISBN = {9783527347506},
url = {http://dx.doi.org/10.1002/9783527826971.ch7},
Abstract = {This chapter introduces a methodology to distinguish the
thermal and nonthermal contributions in an illuminated,
plasmon-enhanced catalyst. Although nonthermal effects in
light-driven reactions are deservedly drawing much
attention, photothermal effects may prove to be even more
beneficial because of the way illumination can tailor
thermal profiles within a catalyst. The technique presented
here extracts the effective thermal and nonthermal reaction
rates under illumination by simultaneously measuring the
total reaction rate and the top- and bottom-surface
temperatures of the catalyst bed. Using these measured
temperatures, a simplified model of the catalyst thermal
profile and effective thermal reaction rates may be deduced
for the illuminated catalysts. Ruthenium and rhodium
photocatalysts with intrinsic plasmonic and catalytic
properties for NH3 synthesis and CO2 hydrogenation were
respectively used to illustrate this technique and examine
thermal, photothermal, and nonthermal reaction rates.
Through innovative experimental techniques, the thermal and
nonthermal contributions may be systematically evaluated to
understand underlying synergistic mechanisms in plasmonic
photocatalysis and extract the nonthermal contribution from
the total measured reaction rate.},
Doi = {10.1002/9783527826971.ch7},
Key = {fds370615}
}
@article{fds360655,
Author = {Chevalier, P and Amirzhan, A and Rowlette, J and Stinson, T and Pushkarsky, M and Day, T and Everitt, HO and Capasso,
F},
Title = {Compact, low threshold methyl fluoride terahertz laser
pumped by a quantum cascade laser},
Journal = {2021 Conference on Lasers and Electro Optics, Cleo 2021
Proceedings},
Year = {2021},
Month = {May},
ISBN = {9781943580910},
Abstract = {We demonstrate a quantum cascade laser-pumped terahertz
laser using methyl fluoride gas. The large dipole moment of
this molecule allows for a low threshold laser with
frequency tunable emission spanning more than one
terahertz.},
Key = {fds360655}
}
@article{fds358757,
Author = {Wang, F and Johnson, SG and Everitt, HO},
Title = {Maximizing Performance of Quantum Cascade Laser-Pumped
Molecular Lasers},
Journal = {Physical Review Applied},
Volume = {16},
Number = {2},
Year = {2021},
Month = {August},
url = {http://dx.doi.org/10.1103/PhysRevApplied.16.024010},
Abstract = {Quantum-cascade-laser-(QCL) pumped molecular lasers (QPMLs)
have recently been introduced as a source of powerful (>1
mW) tunable (>1 THz) narrow-band (<10 kHz) continuous-wave
terahertz radiation. The performance of these lasers depends
critically on molecular collision physics, pump saturation,
and on the design of the laser cavity. Using a validated
three-level model that captures the essential collision and
saturation behaviors of the QPML gas nitrous oxide (N2O), we
explore how the threshold pump power and output terahertz
power depend on the pump power and gas pressure, as well as
on the diameter, length, and output-coupler transmissivity
of a cylindrical cavity. The analysis indicates that maximum
power occurs as pump saturation is minimized in a manner
that depends much more sensitively on pressure than on cell
diameter, length, or transmissivity. A near-optimal compact
laser cavity can produce tens of milliwatts of power tunable
over frequencies above 1 THz when pumped by a multiwatt
QCL.},
Doi = {10.1103/PhysRevApplied.16.024010},
Key = {fds358757}
}
@article{fds359995,
Author = {Khatib, O and Tyler, T and Padilla, WJ and Jokerst, NM and Everitt,
HO},
Title = {Mapping active strain using terahertz metamaterial
laminates},
Journal = {Apl Photonics},
Volume = {6},
Number = {11},
Year = {2021},
Month = {November},
url = {http://dx.doi.org/10.1063/5.0069723},
Abstract = {The ability to image strain fields in composite materials is
an indispensable necessity for structural health monitoring.
Embedded electromagnetic metamaterials sensitive to applied
stresses and operating in the terahertz regime have been
proposed as a solution, but they have traditionally relied
on slight amplitude or frequency shifts of their terahertz
spectral resonance relative to a presumably unchanging,
unstrained reference spectral map. Here, we demonstrate a
facile, reference-free imaging technique to map the
currently active local strain throughout a composite
structure using a reversible passive terahertz metamaterial
laminate with a tailored polarimetric signature. Only two
orthogonal polarizations and a few frequencies are required
to measure this strong terahertz response, from which the
local strain environment may be rapidly and quantitatively
mapped over large areas.},
Doi = {10.1063/5.0069723},
Key = {fds359995}
}
@article{fds362041,
Author = {Amirzhan, A and Chevalier, P and Rowlette, J and Stinson, HT and Pushkarsky, M and Day, T and Everitt, HO and Capasso,
F},
Title = {A quantum cascade laser-pumped molecular laser tunable over
1 THz},
Journal = {Apl Photonics},
Volume = {7},
Number = {1},
Year = {2022},
Month = {January},
url = {http://dx.doi.org/10.1063/5.0076310},
Abstract = {Despite decades of research, no frequency tunable sources
span the terahertz gap between 0.3 and 3 THz. By introducing
methyl fluoride (CH3F) as a new gain medium for a quantum
cascade laser-pumped molecular laser (QPML), we demonstrate
continuous-wave lasing from more than 120 discrete
transitions, spanning the range from 0.25 to 1.3 THz. Thanks
to its large permanent dipole moment and large rotational
constants, methyl fluoride (CH3F) as a QPML gain medium
combines a lower threshold, a larger power efficiency, and a
wider tuning range than other molecules. These key features
of the CH3F QPML, operated in a compact cavity at room
temperature, pave the way to a versatile THz source to
bridge the THz gap.},
Doi = {10.1063/5.0076310},
Key = {fds362041}
}
@article{fds365848,
Author = {Prasad, CS and Yang, F and Li, W and Lach, R and Everitt, HO and Naik,
GV},
Title = {Non-Hermitian metasurface with non-trivial
topology},
Journal = {Optics Infobase Conference Papers},
Year = {2022},
Month = {January},
ISBN = {9781557528209},
Abstract = {The synergy between topology and non-Hermiticity in
photonics holds potential for optical devices that are
robust against defects. We demonstrate a non-Hermitian
plasmonic-dielectric metasurface in the visible with
non-trivial topology.},
Key = {fds365848}
}
@article{fds367336,
Author = {Prasad, CS and Yang, F and Li, W and Lach, R and Everitt, HO and Naik,
GV},
Title = {Non-Hermitian metasurface with non-trivial
topology},
Journal = {2022 Conference on Lasers and Electro Optics, Cleo 2022
Proceedings},
Year = {2022},
Month = {January},
ISBN = {9781957171050},
Abstract = {The synergy between topology and non-Hermiticity in
photonics holds potential for optical devices that are
robust against defects. We demonstrate a non-Hermitian
plasmonic-dielectric metasurface in the visible with
non-trivial topology.},
Key = {fds367336}
}
@article{fds367338,
Author = {Chevalier, P and Amirzhan, A and Rowlette, J and Stinson, HT and Pushkarsky, M and Day, T and Capasso, F and Everitt,
HO},
Title = {The widely tunable quantum cascade laser pumped molecular
laser},
Journal = {Optics Infobase Conference Papers},
Year = {2022},
Month = {January},
ISBN = {9781557528209},
Abstract = {The quantum cascade laser pump molecular laser (QPML) is a
tunable source of terahertz frequencies operating at room
temperature that can easily scale beyond the milliwatt
level. We present here new progress in QPML
research.},
Key = {fds367338}
}
@article{fds369343,
Author = {Schneiderman, M and Reyes, D and Bernath, R and Everitt, HO and Richardson, M},
Title = {Transient Coherence in IR/THz Double Resonance Spectroscopy
for Remote Sensing},
Journal = {Optics Infobase Conference Papers},
Year = {2022},
Month = {January},
ISBN = {9781557528209},
Abstract = {Infrared/Terahertz double resonance spectroscopy is explored
for remote identification of trace molecular gases at
atmospheric pressures. Free induction decay of low pressure
hyperfine-resolved transitions in CH335Cl inform a roadmap
for future atmospheric pressure studies.},
Key = {fds369343}
}
@article{fds362479,
Author = {Yang, F and Prasad, CS and Li, W and Lach, R and Everitt, HO and Naik,
GV},
Title = {Non-Hermitian metasurface with non-trivial
topology},
Journal = {Nanophotonics},
Volume = {11},
Number = {6},
Pages = {1159-1165},
Year = {2022},
Month = {February},
url = {http://dx.doi.org/10.1515/nanoph-2021-0731},
Abstract = {The synergy between topology and non-Hermiticity in
photonics holds immense potential for next-generation
optical devices that are robust against defects. However,
most demonstrations of non-Hermitian and topological
photonics have been limited to super-wavelength scales due
to increased radiative losses at the deep-subwavelength
scale. By carefully designing radiative losses at the
nanoscale, we demonstrate a non-Hermitian
plasmonic-dielectric metasurface in the visible with
non-trivial topology. The metasurface is based on a fourth
order passive parity-time symmetric system. The designed
device exhibits an exceptional concentric ring in its
momentum space and is described by a Hamiltonian with a
non-Hermitian Z 3 ${\mathbb{Z}}_{3}$ topological invariant
of V = -1. Fabricated devices are characterized using
Fourier-space imaging for single-shot k-space measurements.
Our results demonstrate a way to combine topology and
non-Hermitian nanophotonics for designing robust devices
with novel functionalities.},
Doi = {10.1515/nanoph-2021-0731},
Key = {fds362479}
}
@article{fds362478,
Author = {Chevalier, P and Amirzhan, A and Rowlette, J and Stinson, HT and Pushkarsky, M and Day, T and Capasso, F and Everitt,
HO},
Title = {Multi-line lasing in the broadly tunable ammonia quantum
cascade laser pumped molecular laser},
Journal = {Applied Physics Letters},
Volume = {120},
Number = {8},
Year = {2022},
Month = {February},
url = {http://dx.doi.org/10.1063/5.0079219},
Abstract = {Gaseous ammonia has previously been demonstrated as a
compelling gain medium for a quantum cascade laser pumped
molecular laser (QPML) exhibiting good power efficiency.
Here, we explore the potential of the ammonia QPML to
produce powerful, broadly tunable terahertz frequency lasing
on rotational and pure inversion transitions. After
theoretically predicting possible laser frequencies, pump
thresholds, and efficiencies, we experimentally demonstrate
unprecedented tunability - from 0.763 to 4.459 THz - by
pumping Q- and R-branch infrared transitions with widely
tunable quantum cascade lasers. We additionally demonstrate
two types of multi-line lasing: simultaneous pure inversion
and rotation-inversion transitions from the same pumped
rotational state and cascaded lasing involving transitions
below the pumped rotational state. We report single
frequency power levels as great as 0.45 mW from a low volume
laser cavity.},
Doi = {10.1063/5.0079219},
Key = {fds362478}
}
@article{fds362927,
Author = {Bayles, A and Tian, S and Zhou, J and Yuan, L and Yuan, Y and Jacobson, CR and Farr, C and Zhang, M and Swearer, DF and Solti, D and Lou, M and Everitt,
HO and Nordlander, P and Halas, NJ},
Title = {Al@TiO2 Core-Shell Nanoparticles for Plasmonic
Photocatalysis.},
Journal = {Acs Nano},
Volume = {16},
Number = {4},
Pages = {5839-5850},
Year = {2022},
Month = {April},
url = {http://dx.doi.org/10.1021/acsnano.1c10995},
Abstract = {Plasmon-induced photocatalysis is a topic of rapidly
increasing interest, due to its potential for substantially
lowering reaction barriers and temperatures and for
increasing the selectivity of chemical reactions. Of
particular interest for plasmonic photocatalysis are
antenna-reactor nanoparticles and nanostructures, which
combine the strong light-coupling of plasmonic
nanostructures with reactors that enhance chemical
specificity. Here, we introduce Al@TiO<sub>2</sub>
core-shell nanoparticles, combining earth-abundant Al
nanocrystalline cores with TiO<sub>2</sub> layers of tunable
thickness. We show that these nanoparticles are active
photocatalysts for the hot electron-mediated H<sub>2</sub>
dissociation reaction as well as for hot hole-mediated
methanol dehydration. The wavelength dependence of the
reaction rates suggests that the photocatalytic mechanism is
plasmonic hot carrier generation with subsequent transfer of
the hot carriers into the TiO<sub>2</sub> layer. The
Al@TiO<sub>2</sub> antenna-reactor provides an
earth-abundant solution for the future design of
visible-light-driven plasmonic photocatalysts.},
Doi = {10.1021/acsnano.1c10995},
Key = {fds362927}
}
@article{fds365650,
Author = {Lee, SH and Song, Y and Iglesias, B and Everitt, HO and Liu,
J},
Title = {Effect of Humidity on C1, C2Product
Selectivity for CO2Reduction in a Hybrid
Gas/Liquid Electrochemical Reactor},
Journal = {Acs Applied Energy Materials},
Volume = {5},
Number = {8},
Pages = {9309-9314},
Publisher = {American Chemical Society (ACS)},
Year = {2022},
Month = {August},
url = {http://dx.doi.org/10.1021/acsaem.2c02226},
Abstract = {Hybrid gas/liquid-fed electrochemical flow reactors may
become attractive alternatives for chemical synthesis once
it is understood how catalytic product selectivity may be
optimized through the control of gas phase reactants. Using
a constant pH basic electrolyte to suppress the hydrogen
evolution reaction, we explore how protonation by water
vapor added to the flowing CO2supply affects the
CO2reduction reaction. Although H2remains the dominant
product, supplying dry CO2gas selectively produces more
C2products than C1. However, adding protons through water
vapor changes selectivity toward C1products, increasing the
overall faradaic efficiency of hydrocarbon production while
reducing H2production.},
Doi = {10.1021/acsaem.2c02226},
Key = {fds365650}
}
@article{fds365847,
Author = {Lou, M and Bayles, A and Everitt, HO and Halas, NJ},
Title = {Selective Photodetoxification of a Sulfur Mustard Simulant
Using Plasmonic Aluminum Nanoparticles.},
Journal = {Nano Letters},
Volume = {22},
Number = {18},
Pages = {7699-7705},
Year = {2022},
Month = {September},
url = {http://dx.doi.org/10.1021/acs.nanolett.2c03188},
Abstract = {Plasmonic nanostructures have attracted increasing interest
in the fields of photochemistry and photocatalysis for their
ability to enhance reactivity and tune reaction selectivity,
a benefit of their strong interactions with light and their
multiple energy decay mechanisms. Here we introduce the use
of earth-abundant plasmonic aluminum nanoparticles as a
promising renewable detoxifier of the sulfur mustard
simulant 2-chloroethylethylsulfide through gas phase
photodecomposition. Analysis of the decomposition products
indicates that C-S bond breaking is facilitated under
illumination, while C-Cl breaking and HCl elimination are
favored under thermocatalytic (dark) conditions. This
difference in reaction pathways illuminates the potential of
plasmonic nanoparticles to tailor reaction selectivity
toward less hazardous products in the detoxification of
chemical warfare agents. Moreover, the photocatalytic
activity of the Al nanoparticles can be regenerated almost
completely after the reaction concludes through a simple
surface treatment.},
Doi = {10.1021/acs.nanolett.2c03188},
Key = {fds365847}
}
@article{fds367337,
Author = {Lou, M and Bao, JL and Zhou, L and Naidu, GN and Robatjazi, H and Bayles,
AI and Everitt, HO and Nordlander, P and Carter, EA and Halas,
NJ},
Title = {Direct H2S Decomposition by Plasmonic
Photocatalysis: Efficient Remediation plus Sustainable
Hydrogen Production},
Journal = {Acs Energy Letters},
Volume = {7},
Number = {10},
Pages = {3666-3674},
Year = {2022},
Month = {October},
url = {http://dx.doi.org/10.1021/acsenergylett.2c01755},
Abstract = {Plasmonic metal nanostructures have garnered rapidly
increasing interest as heterogeneous photocatalysts,
facilitating chemical bond activation and overcoming the
high energy demands of conventional thermal catalysis. Here
we report the highly efficient plasmonic photocatalysis of
the direct decomposition of hydrogen sulfide into hydrogen
and sulfur, an alternative to the industrial Claus process.
Under visible light illumination and with no external heat
source, up to a 20-fold reactivity enhancement compared to
thermocatalysis can be observed. The substantially enhanced
reactivity can be attributed to plasmon-mediated hot
carriers (HCs) that modify the reaction energetics. With a
shift in the rate-determining step of the reaction, a new
reaction pathway is made possible with a lower apparent
reaction barrier. Light-driven one-step decomposition of
hydrogen sulfide represents an exciting opportunity for
simultaneous high-efficiency hydrogen production and
low-temperature sulfur recovery, important in many
industrial processes.},
Doi = {10.1021/acsenergylett.2c01755},
Key = {fds367337}
}
@article{fds363989,
Author = {Chevalier, P and Piccardo, M and Amirzhan, A and Capasso, F and Everitt,
HO},
Title = {Accurately Measuring Molecular Rotational Spectra in Excited
Vibrational Modes.},
Journal = {Applied Spectroscopy},
Volume = {76},
Number = {12},
Pages = {1494-1503},
Year = {2022},
Month = {December},
url = {http://dx.doi.org/10.1177/00037028221111174},
Abstract = {Although gas phase rotational spectroscopy is a mature field
for which millions of rotational spectral lines have been
measured in hundreds of molecules with sub-MHz accuracy, it
remains a challenge to measure these rotational spectra in
excited vibrational modes with the same accuracy. Recently,
it was demonstrated that virtually any rotational transition
in excited vibrational modes of most molecules may be made
to lase when pumped by a continuously tunable quantum
cascade laser (QCL). Here, we demonstrate how an infrared
QCL may be used to enhance absorption strength or induce
lasing of terahertz rotational transitions in highly excited
vibrational modes in order to measure their frequencies more
accurately. To illustrate the concepts, we used a tunable
QCL to excite v<sub>3</sub> R-branch transitions in
N<sub>2</sub>O and either enhanced absorption or induced
lasing on 20 v<sub>3</sub> rotational transitions, whose
frequencies between 299 and 772 GHz were then measured using
either heterodyne or modulation spectroscopy. The spectra
were fitted to obtain the rotational constants B<sub>3</sub>
and D<sub>3</sub>, which reproduce the measured spectra to
within the experimental uncertainty of ± 5 kHz. We then
show how this technique may be generalized by estimating the
threshold power to make any rotational transition lase in
any N<sub>2</sub>O vibrational mode.},
Doi = {10.1177/00037028221111174},
Key = {fds363989}
}
@article{fds369819,
Author = {Yao, W and Verdugo, F and Everitt, HO and Christiansen, RE and Johnson,
SG},
Title = {Designing structures that maximize spatially averaged
surface-enhanced Raman spectra.},
Journal = {Optics Express},
Volume = {31},
Number = {3},
Pages = {4964-4977},
Year = {2023},
Month = {January},
url = {http://dx.doi.org/10.1364/oe.472646},
Abstract = {We present a general framework for inverse design of
nanopatterned surfaces that maximize spatially averaged
surface-enhanced Raman (SERS) spectra from molecules
distributed randomly throughout a material or fluid,
building upon a recently proposed trace formulation for
optimizing incoherent emission. This leads to radically
different designs than optimizing SERS emission at a single
known location, as we illustrate using several 2D design
problems addressing effects of hot-spot density, angular
selectivity, and nonlinear damage. We obtain optimized
structures that perform about 4 × better than coating
with optimized spheres or bowtie structures and about
20 × better when the nonlinear damage effects are
included.},
Doi = {10.1364/oe.472646},
Key = {fds369819}
}
@article{fds370225,
Author = {Lee, SA and Kuhs, CT and Searles, EK and Everitt, HO and Landes, CF and Link, S},
Title = {d-Band Hole Dynamics in Gold Nanoparticles Measured
with Time-Resolved Emission Upconversion
Microscopy.},
Journal = {Nano Letters},
Volume = {23},
Number = {8},
Pages = {3501-3506},
Year = {2023},
Month = {April},
url = {http://dx.doi.org/10.1021/acs.nanolett.3c00622},
Abstract = {The performance of photocatalysts and photovoltaic devices
can be enhanced by energetic charge carriers produced from
plasmon decay, and the lifetime of these energetic carriers
greatly affects overall efficiencies. Although hot electron
lifetimes in plasmonic gold nanoparticles have been
investigated, hot hole lifetimes have not been as thoroughly
studied in plasmonic systems. Here, we demonstrate
time-resolved emission upconversion microscopy and use it to
resolve the lifetime and energy-dependent cooling of
<i>d</i>-band holes formed in gold nanoparticles by plasmon
excitation and by following plasmon decay into interband and
then intraband electron-hole pairs.},
Doi = {10.1021/acs.nanolett.3c00622},
Key = {fds370225}
}
@article{fds370614,
Author = {Lee, S-H and Iglesias, B and Everitt, HO and Liu,
J},
Title = {Controlling product selectivity in hybrid gas/liquid
reactors using gas conditions, voltage, and
temperature.},
Journal = {Nanoscale},
Volume = {15},
Number = {21},
Pages = {9423-9431},
Year = {2023},
Month = {June},
url = {http://dx.doi.org/10.1039/d3nr00561e},
Abstract = {For the conversion of CO<sub>2</sub> into fuels and chemical
feedstocks, hybrid gas/liquid-fed electrochemical flow
reactors provide advantages in selectivity and production
rates over traditional liquid phase reactors. However,
fundamental questions remain about how to optimize
conditions to produce desired products. Using an alkaline
electrolyte to suppress hydrogen formation and a gas
diffusion electrode catalyst composed of copper
nanoparticles on carbon nanospikes, we investigate how
hydrocarbon product selectivity in the CO<sub>2</sub>
reduction reaction in hybrid reactors depends on three
experimentally controllable parameters: (1) supply of dry or
humidified CO<sub>2</sub> gas, (2) applied potential, and
(3) electrolyte temperature. Changing from dry to humidified
CO<sub>2</sub> dramatically alters product selectivity from
C<sub>2</sub> products ethanol and acetic acid to ethylene
and C<sub>1</sub> products formic acid and methane. Water
vapor evidently influences product selectivity of reactions
that occur on the gas-facing side of the catalyst by adding
a source of protons that alters reaction pathways and
intermediates.},
Doi = {10.1039/d3nr00561e},
Key = {fds370614}
}
@article{fds372215,
Author = {Izadparast, M and Naik, GV and Everitt, HO and Ramezani,
H},
Title = {Exceptional point based lattice gyroscopes},
Journal = {Optical Materials Express},
Volume = {13},
Number = {6},
Pages = {1547-1547},
Publisher = {Optica Publishing Group},
Year = {2023},
Month = {June},
url = {http://dx.doi.org/10.1364/ome.483155},
Abstract = {<jats:p>Ring laser gyroscopes (RLGs) based on non-Hermitian
exceptional points (EPs) have garnered much recent interest
due to their exceptional sensitivity. Such gyroscopes
typically consist of two-ring laser resonators, one with
loss and one with an equal amount of optical gain. The
coupling strength between these ring resonators is a key
parameter determining the sensitivity of EP-based RLGs. Here
we explore how the exceptional sensitivity demonstrated in
this coupled dimer may be further enhanced by adding more
dimers in an array. Specifically, we propose two types of
ring laser gyroscope lattice arrays, each composed of
<jats:italic>N</jats:italic> coupled dimers arrayed serially
or concentrically with periodic boundary conditions, that
guide counter-propagating photons in a rotating frame. Using
coupled mode theory, we show that these lattice gyroscopes
exhibit an enhanced effective coupling rate between the gain
and loss resonators at the EP, thereby producing greater
sensitivity to the angular rotation rate than their
constituent dimers. This work paves the way toward EP-based
RLGs with the necessary sensitivity for GPS-free
navigation.</jats:p>},
Doi = {10.1364/ome.483155},
Key = {fds372215}
}
@article{fds372216,
Author = {Chong, Y and Everitt, HO and Galdi, V and Khajavikhan, M and Naik,
GV},
Title = {Non-Hermitian optics and photonics: introduction to the
special issue},
Journal = {Optical Materials Express},
Volume = {13},
Number = {6},
Pages = {1710-1710},
Publisher = {Optica Publishing Group},
Year = {2023},
Month = {June},
url = {http://dx.doi.org/10.1364/ome.495723},
Abstract = {<jats:p>This is an introduction to the feature issue of
Optical Materials Express on Non-Hermitian Optics and
Photonics.</jats:p>},
Doi = {10.1364/ome.495723},
Key = {fds372216}
}