Teng-Fei Zhang, Guo-An Wu, Jiu-Zhen Wang, Yong-Qiang Yu, Deng-Yue Zhang, Dan-Dan Wang, Jing-Bo Jiang, Jia-Mu Wang, Lin-Bao Luo*
Abstract: In this study, we present a simple ultraviolet (UV) light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365 nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W, and 105, respectively, which were much higher than other ZnO nanostructures based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply-structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices.