Radiation-induced defects in n-type GaN irradiated by 2MeV electrons at room temperature were studied by electron paramagnetic resonance. Four electron paramagnetic resonance spectra, labelled D1–D4, were observed in irradiated n-type GaN. The D1 spectrum was a broad line (~10–12mT in line width) with an isotropic g-value g~2.03 and could be detected, in all the samples studied, at 4 to 300K. The D2 centre had an electron spin S=1/2 and showed a clear hyperfine structure due to interaction with three equivalent 14N. The g-values of the axial configuration were determined to be g|| =2.001 and g⊥=1.999. On the basis of the observed hyperfine structure, formation conditions and annealing behaviour, the D2 defect was assigned to a gallium vacancy–oxygen pair in the negative charge state, (VGaON)–.

Radiation-Induced Defects in GaN. N.T.Son, C.G.Hemmingsson, N.Morishita, T.Ohshima, T.Paskova, K.R.Evans, A.Usui, J.Isoya, B.Monemar, E.Janzén: Physica Scripta, 2010, T141[1], 014015