Interaction of hydrogen with nitrogen interstitials in wurtzite GaN

First-principles techniques are used to investigate the interaction of hydrogen with nitrogen interstitials in wurtzite GaN. The calculations reveal that hydrogen can either compensate an interstitial by donating an electron to an interstitial acceptor level, or passivate the interstitial by forming a hydrogen–interstitial complex. Nitrogen interstitials can bind up to three hydrogen atoms and hydrogen removal energies are computed as a function of the number of hydrogen atoms. Removal energies are found to depend strongly on the Fermi level, and hydrogen-interstitial complexes are predicted to be unstable in n-type GaN. Frequencies are computed for hydrogen vibrations and compared with previously reported infrared absorption measurements on hydrogen-implanted GaN.