Momentum relaxation of electrons in n-type bulk GaN

Abstract

We report on Hall mobility and carrier density measurements on n-type GaN epilayers grown on sapphire by MBE. The results are discussed using a theoretical model that takes into account the most important scattering mechanisms contributing to determining the mobility of electrons in 3D. We show that polar-optical phonon scattering and dislocation scattering dominate at high temperatures especially in samples with low carrier density, while impurity and dislocation scattering take over at low temperatures.