Abstract
We study the epitaxial GaAs-AlAs interface of wide gap materials by full-potential density functional theory. AlAs thin films on a GaAs substrate and GaAs thin films on an AlAs substrate show different trends for the electronic band gap with increasing film thickness. In both cases, we find an insulating state at the interface and a negligible charge transfer even after relaxation. Differences in the valence and conduction band edges suggest that the energy band discontinuities depend on the growth sequence. Introduction of As vacancies near the interface induces metallicity, which opens great potential for GaAs-AlAs heterostructures in modern electronics. (C) 2011 American Institute of Physics. [doi:10.1063/1.3643049]