Doping Properties of Amphoteric C, Si, and Ge Impurities in GaN and AlN

Abstract

Electronic structure of substitutional group-IV impurities C, Si, and Ge in hexagonal GaN and AlN were studied by quantum molecular dynamics. Cis is a very shallow acceptor, and thus a promising p-type dopant. Both Si and Ge are excellent donors in GaN. However, in AlGaN alJoys the DX configurations are stable for a sufficiently high Al content, which quenches the doping efficiency. Electronic structure of nearest-neighbor Χcatiοn—ΧΝ pairs is also discussed. PACS numbers: 71.55.—i