It was found that the 2.5MeV electron irradiation of wurtzite-type material, which had been epitaxially grown onto sapphire substrates, greatly reduced its near-ultraviolet and visible luminescence and produced 2 bands in the near-infrared. In one of these, a broad structure-less band which was centered at about 0.95eV, and 3 optically detected S = 1/2 electron paramagnetic resonances were observed. Two of these exhibited well-resolved hyperfine interaction with a single Ga nucleus; thus suggesting that they were interstitial-Ga related. The second band had a sharp zero-phonon line at 0.88eV, an associated phonon-assisted structure and yielded an S= 1 optically detected electron paramagnetic resonance signal; which was not identified.

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