Native defects and impurities in GaN

Abstract

Using state-of-the-art total energy calculations we investigate defect formation energies and electronic structure for native defects in wurtzite and cubic GaN. The defect formation energies and electronic structures are very similar in both structures. The main difference is a split in the p-like defect states in wurtzite GaN, which are degenerate in cubic GaN. The role of the Ga 3d electrons on the chemical bonding in GaN is discussed in detail. We explain why the deep lying Ga 3d electrons have a remarkably strong influence on defect formation energies and atomic relaxation for some of the defects