Deep centres and dislocation densities, in undoped n-type samples which had been grown via hydride vapour-phase epitaxy, were characterized as a function of the layer thickness by using deep-level transient spectroscopy and transmission electron microscopy. As the layer thickness was decreased, the types and concentrations of the deep centres increased; accompanied by an increase in the dislocation density. On the basis of a comparison with electron irradiation-induced centres, some of the predominant centres in the present material were identified as possibly being point defects such as Ni and NGa.

Evolution of Deep Centres in GaN Grown by Hydride Vapour Phase Epitaxy. Z.Q.Fang, D.C.Look, J.Jasinski, M.Benamara, Z.Liliental-Weber, R.J.Molnar: Applied Physics Letters, 2001, 78[3], 332-4