First‐principles study of the surface phase diagrams of GaN(0001) and (000−1) under oxide vapor phase epitaxy growth conditions

Abstract

First‐principles calculations are used to investigate the stable structures of the GaN(0001) and (000–1) surfaces under oxide vapor phase epitaxy growth conditions. The surface phase diagrams as a function of temperature and Ga pressure are described. It was found that the GaN(0001) surface is covered by OH groups. For the GaN(000–1) surface, the stable surface structure is with H atoms adsorbed on the topmost N atoms or an O atom stably incorporated into the Ga monolayer. We discuss the relationship between the growth conditions and O impurity incorporation. From the results, we suggest that high H2 pressure and high temperature growth conditions are favorable for decreasing O impurity incorporation.