Optical detection of magnetic resonance in electron-irradiated GaN

Four new optically detected magnetic resonances are observed in photoluminescence bands at ∼ 0.85 and ∼0.93 eV, which are produced in epitaxial wurtzite films of GaN by 2.5-MeV electron irradiation. One of these reveals a resolved hyperfine interaction with a single Ga nucleus, indicating a displaced Ga atom of some kind. It is tentatively identified as a complex involving interstitial ${\mathrm{Ga}}_{\mathrm{i}}^{2+}$.