Nanoporous Design for Enhancing Full-Band Solar-Blind Absorption in Ga2O3 Photodetectors

Abstract

Gallium oxide, characterized by its ultra-broad bandwidth, high electron drift velocity, and excellent thermal stability, demonstrates significant potential for solar-blind ultraviolet photodetectors (SBUV-PDs) that can be applied in both military and civilian contexts, such as missile warning, fire detection, and secure communications. However, the conventional metal-semiconductor-metal (MSM) structure of photodetectors results in suboptimal responsivity due to reflection and absorption at the metal-semiconductor interfaces, as well as the inability of the semiconductor to effectively optimize light absorption. In this work, we propose a periodic nanopore design in Ga₂O₃ thin films, which capitalizes the coupling between incident light and the electronic oscillations on the Ga₂O₃ surface, thereby increasing the effective absorption area as well as inducing optical interference within the structure. Compared to the structure without surface modifications, the photodark current ratio (PDCR) increases by an order of magnitude, from 2.39 × 10⁷ to 4.26 × 10⁸, and the responsivity is enhanced by a factor of 5.87, rising from 0.55 to 3.23 A/W. This study is expected to offer a reliable strategy for the fabrication of high-performance SBUV-PDs.