Computational and experimental studies on the growth of nonpolar surfaces of gallium nitride

Abstract

Surface diffusion of the adatoms strongly influences the surface morphology of thin films. We have carried out density functional theory calculations to study the binding energies, migration pathways, and diffusion barriers for adatoms such as Ga and N on the nonpolar surface such as m- and a-plane GaN surfaces and compare it with the results on c-plane GaN surfaces. A strong anisotropy was observed for the diffusion behavior for Ga adatom on m- and a-plane GaN surfaces with the channels of low diffusion barrier in a- and c-crystallographic directions, respectively. The experimental observation during the metal organic chemical vapor deposition growth of m- and a-plane GaN surfaces show striated surface morphology with the steps oriented in a- and c-crystallographic directions, respectively.