Atomic scale morphology, growth behaviour and electronic properties of semipolar GaN surfaces

Abstract

First-principles calculations relating to the atomic structure and electronic properties of {} GaN surfaces reveal significant differentiations between the two polarity orientations. The () surface exhibits a remarkable morphological stability, stabilizing a metallic structure (Ga adlayer) over the entire range of the Ga chemical potential. In contrast, the semiconducting, cleaved surface is favoured on () under extremely and moderately N-rich conditions, a Ga bilayer is stabilized under corresponding Ga-rich conditions and various transitions between metallic reconstructions take place in intermediate growth stoichiometries. Efficient growth schemes for smooth, two-dimensional GaN layers and the isolation of {} material from parasitic orientations are identified.