Distribution of nitrogen atoms in dilute GaAsN and InGaAsN alloys studied by scanning tunneling microscopy

Nitrogen atoms in the cleaved (110) surfaces of dilute GaAsN and InGaAsN al loys have been studied using cross-sectional scanning tunneling microscopy. The distribution of nitrogen atoms in GaAs0.983N0.017 and In0.04Ga0.96As0. 09N0.01 alloys is found to be in agreement with random statistics, with the exception of a small enhancement in the number of [001]-oriented nearest-n eighbor pairs. The effects of annealing on In0.04Ga0.96As0.99N0.01 alloys h as been studied by scanning tunneling spectroscopy. Spectra display a reduc ed band gap compared to GaAs but little difference is seen between as-grown versus annealed InGaAsN samples. In addition, voltage dependent imaging ha s been used to investigate second-plane nitrogen atoms. (C) 2001 American V acuum Society.