ZnO nanowire photodetectors based on Schottky contact with surface passivation

Performance characteristics, such as dark current and response time, of ZnO nanowire (NW) photodetectors are usually degraded by H2O/O2 adsorption on the NW surfaces. In this work, ZnO NW photodetectors based on Au Schottky contact through passivating surface states were investigated. ZnO NW photodetectors were fabricated with a lateral electrode structure, in which Au served as Au/ZnO Schottky contact and semi-transparent top electrode. Specifically, passivation of the surface states of ZnO NWs by using highly intensive UV irradiation effectively improved the photoresponse. A physical model based on surface band theory was developed to understand the origin of the performance improvement of the photodetector. The present device architecture prevents ZnO NWs photodetector from H2O/O2 adsorption in air and efficiently extracts photogenerated carriers across a diametrical direction.