Study on the defects of ZnO nanowire

The room-temperature photoluminescence property of ZnO nanowires was studied. It showed an ultraviolet peak and a visible light band in the PL spectrum. Through Gaussian fitting, it was found that the visible light band can be divided into two peaks at 2.37 eV and 2.53 eV, which was originated from oxygen antisite and oxygen vacancy defects, respectively. After being exposed to air or post-annealed in oxygen ambience, aging effect was observed and the peak at 2.53 eV disappeared due to the removal of oxygen vacancy defects. Therefore, it is suggested that oxygen antisite and oxygen vacancy coexist in ZnO and induce visible light emission.