Fabrication of Rectification Nanosensors by Direct Current Dielectrophoresis Alignment of ZnO Nanowires

This work demonstrates the fabrication and characterization of ZnO nanowire-based devices in a metal–nanowire–metal configuration using the direct current dielectrophoresis alignment across Au electrodes. The current–voltage characteristics of the devices revealed that they were rectifying, and the direction of rectification was determined by the direction of current due to the asymmetric Joule heating in the dielectrophoresis alignment process. Joule heating caused the Au atoms to diffuse from the Au electrodes to the inner ZnO NWs and the formation of Schottky contact at the Au/ZnO interface. A fast and sensitive photoresponse was achieved for the rectifying devices in reverse-biased mode due to the carrier injection and photocurrent gain under UV illumination. Such direct current dielectrophoresis alignment of ZnO nanowires is a facile method for fabricating rectification devices with application in sensitive and fast UV detecting sensors.