Highly sensitive deep ultraviolet to visible photodetector based on backgate regulated selenophosphate In₂P₃Se₉ material

The metal selenophosphate material In₂P₃Se₉ exhibits significant potential for ultraviolet-to-visible photodetection due to its moderate bandgap and ultra-low dark current characteristics. However, its relatively low photocurrent limits its practical application. In this study, we systematically optimized the material thickness and employed an interdigitated electrode structure to enhance light absorption and carrier collection. The resulting photodetector exhibits a broad spectral response from 254 nm (deep ultraviolet) to 980 nm (near infrared), with a rapid response time of 0.6 ms. Notably, the responsivity and detectivity were significantly enhanced by more than 100 times through the electrode design. Moreover, backgate regulation enhanced the responsivity by up to one order of magnitude. The optimized device demonstrated outstanding photodetection performance with a responsivity of 210 A/W and a specific detectivity of 3.5 × 10¹¹ Jones at 638 nm, enabling high-resolution multi-wavelength imaging. This work offers an effective optimization route for In₂P₃Se₉-based photodetectors and advances their potential for practical optoelectronic applications.