Identification of zinc and oxygen vacancy states in nonpolar ZnO single crystal using polarized photoluminescence

Polarized photoluminescence spectra of the nonpolar ZnO single crystals annealed at different temperatures in air were investigated, for which the whole emission spectra from visible up to ultraviolet range for zinc and oxygen defects states are taken separately via the parallel and the crossed polarization geometries, respectively. It is also deduced from the spectra that the density of oxygen vacancy defects attains minimum for the sample annealed at 400 degrees C, and above which both anharmonic effects of ultraviolet emission and enhancement of defect-related deep band emission band due to the increase of oxygen and zinc vacancy defects are observed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3525714]