Interactions of hydrogen with native defects in GaN

The atomic and electronic structure of hydrogen-vacancy complexes in GaN is investigated with pseudopotential-density-functional calculations. Calculated formation energies provide information about the likelihood of incorporation of these complexes in n-type and p-type material, and binding energies provide a measure for the dissociation energy. Vibrational frequencies yield a signature of the complex that should facilitate experimental identification. The behavior of hydrogenated nitrogen vacancies during annealing of acceptor-doped GaN is discussed, and a correlation with the frequently observed luminescence band around 420 nm is proposed.