Atomic-scale models of interactions between inversion domain boundaries and intrinsic basal stacking faults in GaN

Interactions between inversion domain boundaries (IDBs) and intrinsic basal stacking faults (SFs) in wurtzite-structured GaN grown on (0001) sapphire were studied using high-resolution electron microscopy (HREM) observations and empirical potential calculations. In one type of interaction, an SF terminates on an IDB, thereby inducing a transformation from a low-energy and electrically non-active IDB structure to a high-energy, electrically active one. In a second interaction, the SF crosses the IDB without changing its structure. These configurations were topologically established a priori, and were confirmed by experimental observations. It was found that the first junction line exhibits partial dislocation character, while the second is defect-free. Atomic-scale periodic supercells of the interactions have been produced and the relative energy values are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.