Alloy scattering in AlGaN and InGaN: A numerical study

Abstract

Wave-vector-dependent rates of disorder-induced alloy scattering have been computed for wurtzite AlGaN and InGaN to determine the transport properties of III-nitride alloys through full band Monte Carlo simulation. Contrary to previous studies, the empirical selection of a constant alloy scattering potential has been replaced by a more fundamental approach based on detailed information about the electronic structure and the corresponding screened atomic potentials. Band structures and atomic potentials have been determined in the framework of the nonlocal empirical pseudopotential method; good agreement of the fundamental energy gap with available experimental information has been achieved over the entire composition range of the alloys with the inclusion of a disorder contribution in the pseudopotential. The calculated alloy scattering potential is in reasonable agreement with the few indirect measurements available for AlGaN. Calculations of electron steady-state velocity-field curves confirm that alloy scattering has significant effects on the transport properties of AlGaN and InGaN. © 2007 American Institute of Physics.