Defect identification for the AsGa family

Abstract

The AsGa family consists of at least four distinctly different point defects including the technologically important EL2 defect. While the different members are easily distinguished from their MCDA spectra, the differences of the hf and shf interactions as derived from ODEPR and ODENDOR are rather small.We present ab initio calculations using the LMTO–ASA Green's function method for a variety of defect models that might be relevant for the identification of AsGa-related defects. We confirm the identification of the isolated AsGa and show that the {AsGa–X2} defect must be identified with the nearest-neighbor antistructure pair rather than with the {AsGa–VAs} pair. For the {AsGa–X1} defect a distant antistructure pair is a likely candidate. For the EL2, the most important member of the AsGa family, we have not found a conclusive defect model. The recent ODENDOR data are similar to those of the distant orthorhombic {AsGa–VGa} pair, which, however is a triple acceptor and not a donor.