A self-powered and flexible deep ultraviolet photodetector based on NiO/Ga2O3 heterojunction and employing stable MXene electrodes

Abstract

Wearable photodetectors (PDs) have gained significant attention for their importance in smart monitoring applications. The future of wearable electronics emphasizes the development of self-powered devices, necessitating precise material selection and fabrication techniques to achieve optimal electrical and mechanical performance. Traditionally, p-n photodetector junctions have been fabricated using non-oxide materials such as GaN and SiC, but these materials are prone to conductivity degradation due to oxidation of the p-type component. In this investigation, we have successfully engineered a NiO/Ga2O3 heterojunction deep ultraviolet photodetector on both rigid and flexible substrates. The flexible version incorporates Ti3C2TX MXene electrodes, which offer exceptional mechanical stability even in harsh mechanical circumstances. Our photodetector showcases a responsivity of 47 μA/W, a photoresponse time of 0.24 s, a specific detectivity (D*) of 3.84 ×109 jones, and an Ilight/Idark ratio of 121. It also demonstrates excellent repeatability under 254 nm light exposure. The NiO/Ga2O3 heterojunction photodetector exhibits outstanding optoelectronic performance even under harsh mechanical conditions, specifically withstanding 40% stretchability and various bending angles while maintaining self-powered capabilities. This makes it ideal for wearable devices, meeting requirements for both durability and functionality.