The kinetics of Ga and N adatoms on semi-polar GaN(11•2) surfaces under growth conditions were investigated using density-functional total-energy calculations. The energy barrier (1.2eV) for Ga migration on the c(2x2) surface was found to be much higher than that (∼0.4eV), on conventional c-plane (00•1) surfaces; leading to the desorption of both Ga and N atoms under conventional growth conditions. On the other hand, both Ga and N atoms could be adsorbed, and migrate without desorption, on the 1x1 surface. The results implied that either low temperatures or high-Ga pressures, stabilizing the 1x1 surface, were required in order to grow atomically flat GaN on (11•2) orientations; consistent with experimental results.

Ab initio-Based Study for Adatom Kinetics on Semipolar GaN(11•2) Surfaces. T.Akiyama, T.Yamashita, K.Nakamura, T.Ito: Japanese Journal of Applied Physics, 2009, 48[12], 120218