The 2.5MeV electron irradiation of wurtzite phases which were epitaxially grown onto sapphire substrates greatly reduced the near-ultraviolet and visible luminescence, and produced 2 bands in the near-infrared. In one of these, a broad structureless band which was centered at 0.95eV, 3 optically detected S = 1/2 electron paramagnetic resonances were observed. Two of these exhibited well-resolved hyperfine interactions with a single Ga nucleus; thus suggesting that they were related to interstitial Ga. The second band had a sharp zero-phonon line at 0.88eV, an associated phonon-assisted structure and included an unidentified S = 1 optically detected electron paramagnetic resonance signal.

Optical Detection of Electron Paramagnetic Resonance in Electron-Irradiated GaN C.Bozdog, H.Przybylinska, G.D.Watkins, V.Härle, F.Scholz, M.Mayer, M.Kamp, R.J.Molnar, A.E.Wickenden, D.D.Koleske, R.L.Henry: Physical Review B, 1999, 59[19], 12479-86