A Self-Powered UV Photodetector Using Face-To-Face Zinc Oxide Nanorod Arrays

We report a self-powered ultraviolet (UV) photo- detector (PD) utilizing two sets of free-standing ZnO nanorod arrays (ZNRAs) to assemble as a face-to-face nanohybrid structure. In comparison with the PDs based on single-side ZNRAs, the face-to-face ZNRAs based PD exhibits "1+1>2"enhancements in photoelectric conversion. The ZNRAs were prepared on ITO/glass and Ti foil using a facile hydrothermal method. The face-to-face ZNRAs device operates with the Schottky junctions in ITO/ZnO interface, ohmic contact in Ti/ZnO interface, and the effective NR-NR contacts in neighboring ZNRs as a transport network of carriers. Thanks to the Schottky and NR-NR junction barriers, the electron-hole pairs are effectively separated. The device exhibits a self-powered current density of 5.52 μA•cm−2 and a responsivity of 1.81 mA•W-1 under an irradiation of 3.06 mW•cm-2, and a photogain of 0.80% at photon absorption rate of 5.6×1015 s-1. It is considered that face-to-face ZNRAs could be a promising candidate for high-efficiency photo-detection.