Published in J. Vac. Sci. Technol. B 19, 1644 (2001).

Distribution of Nitrogen Atoms in Dilute GaAsN and InGaAsN Alloys studied by Scanning Tunneling Microscopy

H. A. McKay*, R. M. Feenstra*, T. Schmidtling**, U. W. Pohl**, and J. F. Geisz***
*Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
**Technische Universitaet Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany
***National Renewable Energy Laboratory, Golden, Colorado 80401


Nitrogen atoms in the cleaved (1 -1 0) surfaces of dilute GaAsN and InGaAsN alloys have been studied using cross-sectional scanning tunneling microscopy. The distribution of nitrogen atoms in GaAs0.983N0.017 and In0.04Ga0.96As0.99N0.01 alloys is found to be in agreement with random statistics, with the exception of a small enhancement in the number of [001]-oriented nearest neighbor pairs. The effects of annealing on In0.04Ga0.96As0.99N0.01 alloys has been studied by scanning tunneling spectroscopy. Spectra display a reduced band gap compared to GaAs but little difference is seen between as-grown versus annealed InGaAsN samples. In addition, voltage dependent imaging has been used to investigate second-plane nitrogen atoms.

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