The atomic structures of various N-H complexes in GaAs and GaAs1-xNx alloys was investigated by performing first-principles pseudopotential calculations within the local-density-functional approximation. For GaAs with low H concentrations, it was suggested that N formed a N-H(BC) complex, where H was positioned at a bond-center site between a substitutional N and one of the neighboring Ga atoms. For very high H concentrations, an optically inactive N-H2*(BC-ABN) complex, which corresponds to a configuration of H2* in the vicinity of N, was suggested to be an energetically favorable structure. These atomic models explain many experimental features observed in GaAs and GaAs1-xNx alloys, which contain both N and H.
Nitrogen-Hydrogen Complexes in GaAs and GaAs1-xNx Alloys. Y.S.Kim, K.J.Chang: Physica Status Solidi B, 2003, 235, 121-5