Band offset of GaAs/AlxGa1-xAs heterojunctions from atomistic first principles

Using an atomistic first principles approach, we investigate the band offset of the GaAs/AlxGa1-xAs heterojunctions for the entire range of the Al doping concentration 0 < x <= 1. We apply the coherent potential approach to handle the configuration average of Al doping and a recently proposed semi-local exchange potential to accurately determine the band gaps of the materials. The calculated band structures of the GaAs, AlAs crystals and band gaps of the AlxGa1-xAs alloys, are in very good agreement with the experimental results. We predict that valence band offset of the GaAs/AlxGa1-xAs heterojunction scales with the Al concentration x in a linear fashion as VBO(x) similar or equal to 0.587x, and the conduction band offset scales with x in a nonlinear fashion. Quantitative comparisons to the corresponding experimental data are made. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4800845]