Enhancing the performance of Self-Powered Deep-Ultraviolet photoelectrochemical photodetectors by constructing α-Ga2O3@a-Al2O3 Core-Shell nanorod arrays for Solar-Blind imaging

With the advancement of Ga2O3-based deep-ultraviolet (DUV) photodetectors (PDs), the integration of PDs into array image sensors has become a sought-after objective. However, while solar-blind imaging research primarily revolves around solid-state Ga2O3-based PDs, there remains a significant gap in the exploration of novel photoelectrochemical (PEC) PDs for solar-blind imaging applications. In this study, self-powered solar-blind PEC-PDs with enhanced performance are fabricated based on α-Ga2O3@a-Al2O3 core–shell nanorod arrays (NRAs). Under DUV irradiation and without external bias, the α-Ga2O3@a-Al2O3 devices demonstrate remarkable superiority over α-Ga2O3 devices. When the light intensity was at 0.50 mW cm−2, the photocurrent density notably rises from 4.60 to 11.24 μA cm−2, accompanied by a corresponding increase in responsivity from 9.60 to 22.70 mA W−1. The enhanced performance is attributed to the α-Ga2O3@a-Al2O3 heterostructure, which establishes a built-in electric field facilitating the separation and directed transport of photogenerated carriers at the interface. Moreover, for the first time, a 5 × 5 matrix of α-Ga2O3@a-Al2O3 core–shell NRAs-based PEC-type PDs is employed to demonstrate a proof-of-concept for self-powered solar-blind imaging, capable of effectively capturing the shapes of the letters "C" and "N". This work underscores the immense potential of Ga2O3-based PEC-type PDs for future large-area solar-blind imaging applications.