Electron Irradiation Induced Deep Centers In Hydrothermally Grown Zno

An n-type hydrothermally grown ZnO sample becomes semi-insulating (rho similar to 10(8) Omega cm) after 1-MeV electron-irradiation. Deep traps produced by the irradiation were studied by thermally stimulated current spectroscopy. The dominant trap in the as-grown sample has an activation energy of 0.24 eV and is possibly related to Li(Zn) acceptors. However, the electron irradiation introduces a new trap with an activation energy of 0.15 eV, and other traps of energy 0.30 and 0.80 eV, respectively. From a comparison of these results with positron annihilation experiments and density functional theory, we conclude that the 0.15-eV trap may be related to V(Zn).(c) 2007 American Institute of Physics.