Experimental and theoretical evidence was presented for the metastability of O donors in this material. As the Al content was increased, Hall effect measurements revealed an increase, in the electron activation energy, which was consistent with the emergence of a deep DX level from the conduction band. After exposure to light, persistent photoconductivity was observed in O-doped Al0.39Ga0.61N, at temperatures below 150K, with an optical threshold energy of 1.3eV. A configuration coordinate diagram was deduced from first-principles calculations, and yielded values for the capture barrier, emission barrier, and optical threshold which were in good agreement with the experimental data.

M.D.McCluskey, N.M.Johnson, C.G.Van de Walle, D.P.Bour, M.Kneissl, W.Walukiewicz: Physical Review Letters, 1998, 80[18], 4008-11