Structural analysis of dilute-nitride zinc blende InxGa1-xNyAs1-y cluster by a semiempirical quantum chemistry study

We have studied the total energy of a series of dilute-nitride zinc blende InxGa1-xNyAs1-y cluster configurations using a semiempirical quantum chemistry method. It was found that In-N bonding is favorable from an energy point of view when the N atom is substitutional (replacing an As atom at the regular zinc blende lattice site) and the In mole fraction is smaller than 25%. In-N bonding is always favorable when the N atom is interstitial. Furthermore, an analysis of the incorporation of N-N pairs showed that substitutional incorporation is favored over interstitial. In addition, the dissociation of a N-N pair was found to depend on the local environment, being either In rich or In-free, along the dissociation trajectory when the average In mole fraction is high. The theoretical results are in agreement with experimental results. (c) 2007 American Institute of Physics.