The structures and electronic activities of various types of dislocation, in hexagonal and cubic material, were calculated by using first-principles methods. It was found that most of the stoichiometric dislocations which were investigated in hexagonal samples did not introduce deep acceptor states and could therefore not be responsible for the yellow luminescence. On the other hand, electrically active point defects such as Ga vacancies and O-related defect complexes could be trapped in the stress fields of the dislocations and could be responsible for this luminescence. In the case of cubic samples, it was found that the ideal stoichiometric 60° dislocation was electrically active and that the glide set was more stable than the shuffle.

Dislocations in Hexagonal and Cubic GaN. A.T.Blumenau, J.Elsner, R.Jones, M.I.Heggie, S.Oberg, T.Frauenheim, P.R.Briddon: Journal of Physics - Condensed Matter, 2000, 12[49], 10223-33