On the basis of first-principles calculations, it was found that substitutional N atoms in GaAs acted as H traps; forming N-H complexes. At low H concentrations, the formation of N-monohydride complexes was proposed. This explained various experimental features such as the Fermi-level dependence of the formation of N-H complexes, H vibrational frequencies, isotope shift and photo-conversion of the complexes. At very high H concentrations, the energetically favorable structure was an optically inactive N-dihydride complex which suppressed N-related photoluminescence lines in N-containing GaAs and induced a blue-shift of the band-gap in GaAs1–xNx alloys.

Nitrogen-Monohydride versus Nitrogen-Dihydride Complexes in GaAs and GaAs1–xNx Alloys. Y.S.Kim, K.J.Chang: Physical Review B, 2002, 66[7], 073313 (4pp)