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

The heterojunction ultraviolet photodetectors (UV PDs) were fabricated by growing NiO nanosheets on TiO2 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 x 10(12) Jones under 365 nm UV illumination at zero bias.