Preparation of p-SnO/n-ZnO Heterojunction Nanowire Arrays and Their Optoelectronic Characteristics under UV Illumination

In this work, the use of a ZnO-nanowire (NW)-based heterojunction array structure for application to UV sensors is proposed. Nano-heterojunction arrays (NHAs) were formed via the oblique-angle sputtering deposition of p-type tin monoxide onto vertically aligned ZnO-NWs grown by hydrothermal growth (HTG). The current density–voltage (J–V) curve in darkness shows that the prepared SnO/ZnO-NW NHAs have rectifying current–voltage characteristics. They also exhibit a superior response to UV (254 nm) light illumination. The optoelectronic properties of the SnO/ZnO-NW NHAs with different SnO thicknesses (50–1000 nm) under different UV light intensities (2–6 mW/cm2) were investigated and discussed. UV sensitivity (IUV/Idark) as high as 8.5 was obtained.