Graphene/ZnO nanowire/graphene vertical structure based fast-response ultraviolet photodetector

We report the high performance vertical ultraviolet (UV) photodetectors based on single ZnO nanowire (NW) sandwiched between two graphene sheets. The photocurrent on-off ratio, rising time, and recovery speed of our UV detectors are 8 x 10(2), 0.7 s, and 0.5 s, respectively, which are significantly improved compared to the conventional ZnO NWs photodetectors. The improved performance is attributed to the existence of Schottky barriers between ZnO NW and graphene electrodes. The graphene/ZnO NW/graphene vertical sandwiched structures may be promising candidates for integrated optoelectronic sensor devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4724208]