ALD oxygen vacancy-rich amorphous Ga₂O₃ on three-dimensional urchin-like ZnO arrays for high-performance self-powered solar-blind photodetectors

Abstract

The exploration of efficient self-powered solar-blind photodetectors is essential for applications in future sustainable optoelectronic systems. Herein, we demonstrate a photoelectrochemical (PEC)-type heterojunction-driven solar-blind detector constructed by atomic layer deposition (ALD) of oxygen vacancy-rich amorphous Ga₂O₃ on three-dimensional urchin-like ZnO nanorod arrays (3D V_O-Ga₂O₃/ZnO). The as-fabricated device achieves excellent solar-blind photodetection performance in terms of a high photoresponsivity of 7.97 mA W^-1 at 0 V bias, an ultrahigh light to dark ratio of 6.93 × 10⁴ under 266 nm light illumination as well as fast response and recovery times. The excellent performance originates from abundant oxygen vacancies in a-Ga₂O₃ as donors, high specific surface area and good interface contact enabled by the 3D ordered nanostructure, and high carrier separation rates benefited from the Ga₂O₃/ZnO heterojunction. Our research offers a feasible and cost-effective approach towards the realization of a high-performance self-powered photodetection system for various applications.