A self-powered dual-functional hybrid Cu2O/SiNWs heterojunction with applications in broadband photodetectors and ozone gas sensors

Abstract

Dual-functional sensors can replace two or more individual sensors in a platform so they decrease the system area. However, these devices have a major limitation in that they feature high power consumption. A self-powered dual-functional device that detects broadband light detecting and senses ozone (O 3 ) is reported. The device architecture features a solution-processed Cu 2 O thin film that covers silicon nanowire (SiNW) arrays to form a heterojunction. The hybrid Cu 2 O/SiNWs heterojunction structure allows light trapping and gas adsorption because it has a large specific interface area. The proposed device generates an open-circuit voltage of 0.36 V when illuminated using visible-light and can be used to detect various concentrations of O 3 with excellent selectivity and long-term stability. This Cu 2 O/SiNW heterojunction structure shows that capability to develop self-powered dual-functional sensors in the future. • A self-powered dual-functional device with a hybrid Cu 2 O/SiNWs heterojunction is fabricated to detect broadband light and sense O 3 gas. • Upon exposure to 5 ppm O 3 , V oc increases from 0.36 V to 0.53 V, so it can be used to measure different O 3 concentrations. • The device acting as a photodetector exhibits a relatively high responsivity (0.13 A/W) with fast response speed (< 50 ms). • The device serving as a gas sensor exhibits a relatively high gas response (47%) at zero bias.