Influence of electron irradiation on hydrothermally grown zinc oxide single crystals

The resistivity of hydrothermally grown ZnO single crystals increased from ∼10 3 Ω cm to ∼10 6 Ω cm after 1.8 MeV electron irradiation with a fluence of ∼10 16 cm -2, and to ∼10 9 Ω cm as the fluence increased to ∼10 18 cm -2. Defects in samples were studied by thermally stimulated current (TSC) spectroscopy and positron lifetime spectroscopy (PLS). After the electron irradiation with a fluence of 10 18 cm -2, the normalized TSC signal increased by a factor of ∼100. A Zn vacancy was also introduced by the electron irradiation, though with a concentration lower than expected. After annealing in air at 400°C, the resistivity and the deep traps concentrations recovered to the levels of the as-grown sample, and the Zn vacancy was removed. © 2008 IOP Publishing Ltd.