High-performance Self-powered NiO/Ga2O3 Heterojunction Solar-Blind Photodetector Driven by a Strong Built-in Electric Field

Abstract

Abstract The self-powered solar-blind photodetector offers irreplaceable advantages for applications such as wearable electronics and ultra-low power systems, but their performance is often limited due to the absence of an external bias. In this work, we demonstrate a highperformance self-powered photodetectors based on a well-designed NiO/Ga₂O₃ p-i-n heterostructure that requires no complex pre-treatment methods. The photodetector exhibits a high photo-to-dark current ratio of 378, a high responsivity of 137 mA/W, and fast response times of 27 ms/650 ms. Furthermore, we address the common lack of discussion on the physical origin of self-powered behaviour in other studies. The analysis of the p⁺-n⁻ one-sided abrupt junction, based on repeatable capacitance-voltage characterization, confirmed the presence of a strong built-in electric field with a calculated maximum field strength of 136 kV/cm. It is the fundamental driving force for the photodetector's excellent self-powered performance.