Electrical properties, admittance, and microcathodoluminescence spectra were compared for p-GaN samples grown by hydride vapour-phase epitaxy and by molecular beam epitaxy. The former were characterized by a high 300K hole concentration and a weak temperature dependence of the conductivity. The latter samples showed strongly temperature-activated conductivity due to ionization of Mg acceptors. The main effects of neutron irradiation were similar for the p-HVPE and the p-MBE materials: a compensation of p-type conductivity starting with neutron fluences exceeding 2 x 1016/cm2 and conversion to high resistivity n type with the Fermi level pinned near Ec-(0.8–0.9)eV after irradiation with high doses of 1018/cm2. For the heavily neutron irradiated p-HVPE samples, a strong increase was observed in the c-lattice parameter which indicated an important role for interstitial-type defects.

Neutron Irradiation Effects in p-GaN. A.Y.Polyakov, N.B.Smirnov, A.V.Govorkov, A.V.Markov, N.G.Kolin, D.I.Merkurisov, V.M.Boiko, K.D.Shcherbatchev, V.T.Bublik, M.I.Voronova, S.J.Pearton, A.Dabiran, A.V.Osinsky: Journal of Vacuum Science & Technology B, 2006, 24[5], 2256-61