Thermally stimulated current studies on deep levels in hydrothermally grown single crystal ZnO bulk

摘要

The evaluation of the deep levels in hydrothermally grown ZnO single crystal bulk is studied using a thermally stimulated current (TSC) method with excitation above (below) the band gap. Two broad TSC spectra are resolved by four traps, P_1 (165 meV), P_2 (255 meV), P_3 (300 meV), and P_4 (375 meV). P_2, P_3, and P_4 traps are responsible for excitation by the blue and green lights, but P_1 trap is weakly responsible. Possible origins of P_1 and P_2 are attributed to native point defects and Li acceptor, respectively. P_3 is correlated to oxygen vacancy as an origin of the green luminescence.