Adiabatic Potential for Conformational Change of VGa–VN Complex Defects in GaN

Abstract

Focusing on a VGa–VN complex vacancy defect in GaN, the adiabatic potential for conformational changes of the VGa–VN is investigated using the density functional theory. There are two types of configurations due to the symmetry of the crystal, it is confirmed that there is almost no difference in their stability or electronic state. Using these configurations as the initial and final states, the defect reaction is analyzed when VGa–VN moves using the climbing‐image nudged elastic band method. The reaction barrier for the migration of VGa (VN) is found to be 2.2 (3.3) eV. It is concluded that these reactions occur frequently as GaN is annealed since the atomic diffusion potential barrier is similar to that in other semiconductors. These results suggest that VGa–VN in GaN moves through the crystal as a pair of vacancies by alternately repeating the VGa and the VN migration. These results provide important knowledge for elucidating the microscopic mechanism of the experimentally observed VGa–VN aggregation reaction.