Empirical pseudo potential method for the energy gaps and optical properties of XN (X = Al, Ga, B) and their alloys materials Journal of Physics: Conference Series

Abstract

The pseudo potential method associated with the improved virtual crystal approximation (VCA) is used to calculate symmetric and anti-symmetric form factors for BN, AlN, GaN and to predict the electronic band structure of the zinc-blende BxAlYGa1-x-yN alloys lattice matched to AlN. The optical properties of these alloys are calculated. The range of compositions for which the alloys are lattice-matched to AlN substrate is determined. We find that the addition of boron to the AlGaN alloys decreases the direct gap (EΓΓ) and a direct to indirect transition occurs at a Al concentration of about 0.5 (y = 0.5), which corresponds to a band gap energy of about 4.75 eV.