Photodetector fabrication based on heterojunction of CuO/SnO2/Si nanostructures

Photodetector (PD) was successfully fabricated based on p-CuO NPs/n-SnO2 NWs/Si heterojunction. SnO2 nanowires (SnO2 NWs) on a silicon substrate were first synthesized via chemical vapour deposition (CVD) followed by the deposition of copper oxide nanoparticles (CuO NPs) using the drop-casting technique. The films were characterized by X-ray diffraction and scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Subsequently, two steps of PD fabrications were conducted for SnO2 NWs/Si and CuO/SnO2/Si films. The dark I–V characteristics of SnO2/Si and CuO/SnO2/Si heterojunction exhibit a rectification property. The PD response of SnO2/Si has a sharp cutoff at a wavelength around 390 nm, while the CuO/SnO2/Si nanostructures displayed response at wavelengths in the red UV region (~400 nm). The responsivity and quantum efficiency of SnO2/Si and CuO/SnO2/Si heterojunction are about 0.057–0.33 A/W and 17–94%, respectively. The results of p-n heterojunctions based on CuO NPs/SnO2 NWs/Si revealed an efficiency enhancement of the visible-blind SnO2 photodiodes representing a feasible route for building UV optoelectronic devices based on cost-effective materials.