Surface reconstruction and As surfactant effects on MBE-grown GaN epilayers

Surface reconstructions and their transitions have been examined for MBE grown GaN surfaces. Several types of reconstructions and their transitions were observed depending on growth condition, crystal structure etc. It is shown that the surface reconstruction phase diagram and its phase transition line are useful for the optimization of MBE growth of GaN. Little amount of As-4 residual pressure was found to affect the structure of GaN growing surfaces. These As surfactant effects are discussed and the growth of cubic GaN under small amount of As-4 pressure is reported.