Photoluminescence investigation about zinc oxide with graphene oxide & reduced graphene oxide buffer layers.

ZnO with graphene oxide (GO-ZnO) & reduced graphene oxide (rGO-ZnO) buffer layers were fabricated. Photoluminescence (PL) properties of GO-ZnO and rGO-ZnO compositions induced by oxygen vacancies defects were investigated using photoluminescence spectroscopy. The results showed that blue emission is quenched while yellow-orange emissions from GO-ZnO and rGO-ZnO compositions are significantly increased as compared to that of ZnO films. In stark contrast to enhanced yellow-orange emissions, PL spectra show three sharp, discrete emissions that characterize the dominant optical active defect, which is the oxygen vacancies and extended oxygen vacancies. Our results highlight the ability of GO & rGO buffer layers to modulate defect concentrations in ZnO and contribute to understanding the optical properties of deep-level defects, which is significant for development of long-wavelength photoelectric devices related with graphene materials. Crown