Enhanced back-illuminated Ga2O3-based solar-blind ultraviolet photodetectors

Ga 2 O 3 is a promising material for deep-ultraviolet (DUV) photodetectors due to its ultra-wide bandgap and high thermal and chemical stability. However, because of their relatively low responsivity, Ga 2 O 3 -based photodetectors still have difficulty meeting the requirements of practical applications. Here, we construct a high-performance Ga 2 O 3 photodetector realized by back-illumination. Utilizing high-crystallinity epitaxially grown Ga 2 O 3 as the DUV absorbing layer and the double-polished Al 2 O 3 substrate as the transparent window for injection of photons, the device operating in the back-illuminated mode exhibits a higher DUV photoresponse and faster response speed than in the front-illuminated mode. Therefore, our experimental results have led to the development of a novel strategy for designing and fabricating high-performance Ga 2 O 3 photodetectors.