Visible light sensitive cupric oxide metal-semiconductor-metal photodetectors

The visible light response of Ag-CuO-Ag metal-semiconductor-metal (MSM) photodetector is presented. Electron beam deposited CuO thin films consisted of tightly packed nanocrystallites in monoclinic phase. The observed red-shifts in indirect band-gap from 1.09 eV to 0.99 eV and direct band-gap from 2.92 eV to 2.87 eV, with annealing temperature, is attributed to the weak quantum confinement effect. CuO thin films annealed at 500 °C have a p-type conductivity of 4.33 × 10−2 (ohm-cm)−1 and mobility of 13.2 cm2/V-s. Significant responsivities of 0.33 mA/W and 0.59 mA/W for blue and red lights, respectively, in Ag-CuO-Ag photodetector are illustrative for using it as visible light sensor.