Defects produced in ZnO by 2.5-MeV electron irradiation at 4.2 K: Study by optical detection of electron paramagnetic resonance

Abstract

The effect of 2.5 MeV electron irradiation in situ at 4.2 K on the properties of single crystalline ZnO is studied by photoluminescence (PL) and optically detected electron paramagnetic resonance (ODEPR). A new PL band is produced by the irradiation, and several annealing stages are observed upon annealing to room temperature, the first starting at $\ensuremath{\sim}110\mathrm{K}.$ Three new ODEPR signals are observed in the PL whose emergence and disappearance correlate with the PL changes. The annealing stages are taken as evidence of host interstitial atom migration beginning at the 110 K anneal. No hyperfine structure is observed for the ODEPR signals, so the defects involved cannot be identified at this stage.