Influence of intrinsic or extrinsic doping on lattice locations of carbon in semi-insulating GaN

Abstract

We demonstrate that different doping approaches can significantly influence the lattice locations of carbon (C) in GaN grown by MOCVD. For intrinsically doped GaN with TMGa as the C source, an annealing induced switching process of C atoms from Ga sites to N sites is observed, revealing the existence of substitutional C atoms on both Ga and N sites. While for extrinsically doped GaN with propane as the C precursor, C atoms incorporate almost on N sites. From the viewpoint of growth dynamics, we propose a mechanism for C incorporation into different lattice locations.