Density functional calculations were used to study the binding energies and diffusion barriers for adatoms on GaN surfaces. The energies and barriers were calculated for Ga and N adatoms on both Ga-terminated and N-terminated (00•1) surfaces, as subjected to hydrostatic compressive and tensile strains in the range of 0 to 5%. The barrier to Ga adatom diffusion was greatest for 1% compressive strain, and decreased rapidly at higher strains. The barrier to N adatom diffusion was lowest for 1% tensile strain, and increased as the strain increased on a N-terminated surface. The changes could explain differences in the optimum growth conditions on bulk III-nitride substrates as compared with III-nitride template layers grown onto foreign substrates.

Density Functional Calculations of the Strain Effects on Binding Energies and Adatom Diffusion on (0001) GaN Surfaces. J.R.Grandusky, V.Jindal, J.E.Raynolds, S.Guha, F.Shahedipour-Sandvik: Materials Science and Engineering B, 2009, 158[1-3], 13-8