Nitrogen local electronic structure in Ga(In)AsN alloys by soft-x-ray absorption and emission: Implications for optical properties

Soft-x-ray-emission and -absorption spectroscopies with their elemental specificities are used to determine the local electronic structure of N atoms in Ga(In)AsN diluted semiconductor alloys (N concentrations about 3%) in view of applications of such materials in optoelectronics. Deviations of the N local electronic structure in Ga(In)AsN from the crystalline state in GaN are dramatic in both valence and conduction bands. In particular, a depletion of the valence-band maximum in the N local charge, taking place at the N impurities, appears as one of the fundamental origins of reduced optical efficiency of Ga(In)AsN. Incorporation of In in large concentrations forms In-rich N local environments such as In4N which become the main recombination centers in GaInAsN. Furthermore, a k character of some valence and conduction states, despite the random-alloy nature of Ga(In)AsN, manifests itself in resonant inelastic x-ray scattering.