Atomic scale simulations of arsenic-vacancy complexes in germanium and silicon

Atomistic simulation is used to study vacancy-assisted defect interactions in germanium (Ge). The structures and relative energies of a series of different arsenic (As)-vacancy complexes in Ge are considered. In all cases the calculations use a plane-wave basis set and pseudo -potentials within the generalized gradient approximation (GGA) of density functional theory (DFT). The technique is also used to model equivalent defects in silicon (Si) and predictions show good correspondence to the results of previous experimental and modelling studies. The calculations for Ge also indicate important differences in the binding energies of several As-vacancy and related complexes in Ge compared to Si. (C) 2006 Elsevier Ltd. All rights reserved.