Mg doping affects dislocation core structures in GaN
Rhode, S K and Horton, M K and Kappers, M J and Zhang, S and Humphreys, C J and Dusane, R O and Sahonta, S L and Moram, M A
Aberration-corrected scanning transmission electron microscopy was used to investigate the core structures of threading dislocations in undoped GaN films with both high and low dislocation densities, and in a comparable high dislocation density Mg-doped GaN film. All a-type dislocations in all samples have a 5/7-atom core structsure. In contrast, most (a+c)-type dislocations in undoped GaN dissociate due to local strain variations from nearby dislocations. In contrast, Mg doping prevents (a+c)-type dislocation dissociation. Our data indicate that Mg affects dislocation cores in GaN significantly.
Department of Materials
Imperial College London
Royal School of Mines
London, SW7 2AZ - UK