Density functional theoretical study of surface structure and adatom kinetics for wurtzite AlN

Density-functional calculations concerning the structure and stability of wurtzite AlN surfaces are presented. Specifically, (0001) and (0001¯) polar surfaces and (11¯00) and (112¯0) nonpolar surfaces are discussed in detail. Binding energies, migration pathways, and diffusion barriers for relevant adatoms such as Al, Ga, and N on these polar and nonpolar surfaces are determined. The calculation indicates low diffusion barrier for Al adatom on Al terminated (0001) surface, whereas the N adatom seems to have lower diffusion barrier on N terminated (0001¯) surfaces. A strong anisotropy was observed for diffusion behavior for Al adatom on (11¯00) and (112¯0) surfaces in the [112¯0] and [0001] directions, respectively.