Self-powered heterojunction ultraviolet photodetector based on NiO nanosheets/TiO₂ nanorods

Abstract

The heterojunction ultraviolet photodetectors (UV PDs) were fabricated by growing NiO nanosheets on TiO 2 nanorod arrays (NRs) via hydrothermal method and their UV photoresponse properties were examined. The crystal structure, and optical properties of heterojunction were characterized by X-ray diffraction (XRD), Raman, absorption and photoluminescence (PL) spectra. The results of X-ray photoelectron spectroscopy (XPS) valence band (VB) spectrum, Mott–Schottky (M–S) curves and electrochemical impedance spectroscopy (EIS) of heterojunctions reveal the separation and transfer of photo-generated carriers in heterojunction interface. The UV PDs exhibit a large responsivity of 0.54 A/W and a high detection sensitivity of 6.0 × 10 12 Jones under 365 nm UV illumination at zero bias.