Publications by April S. Brown.

Papers Published

  1. Brown, April S. and Losurdo, Maria and Capezzuto, Pio and Bruno, Giovanni and Brown, Terence and May, Gary, Fundamental reactions controlling anion exchange during mixed anion heterojunction formation: Chemistry and kinetics of P-for-As exchange reaction, Journal of Applied Physics, vol. 99 no. 9 (2006), pp. 093510 - [1.2194126] .
    (last updated on 2007/04/14)

    Abstract:
    The fundamental chemical and kinetic surface processes governing the P-for-As exchange reaction during epitaxial layer synthesis are investigated. Exposure of a GaAs surface to phosphorus molecular beams (P2) is carried out to create superlattice structures realized by surface reactions. The impact of the GaAs surface reconstruction, the P-soak time, and the surface temperature on the extent of intermixing and on the mechanism governing the anion exchange has been studied using x-ray diffraction, spectroscopic ellipsometry, x-ray photoelectron spectroscopy, and atomic force microscopy. It is found that As-rich GaAs surface reconstructions inhibit P-for-As exchange. The extent of the anion exchange increases with temperature. Furthermore, the P-for-As exchange is not controlled by P diffusion into the GaAs. We propose a chemical model that includes P chemisorption and indiffusion, and the competition between P-for-As anion exchange and the formation of AsP isoelectronic compounds. © 2006 American Institute of Physics.

    Keywords:
    Reaction kinetics;Surface properties;Epitaxial growth;Superlattices;Semiconducting gallium compounds;X ray diffraction analysis;Ellipsometry;X ray photoelectron spectroscopy;Ion exchange;Chemisorption;