A graphene-enhanced PEDOT:PSS/β-Ga2O3 microwire organic–inorganic hybrid heterojunction self-driven photodetector with high light responsivity

Abstract

In this study, a PEDOT:PSS@graphene composite structure was engineered by incorporating graphene into PEDOT:PSS, thereby significantly enhancing its electrical conductivity. This composite layer was subsequently integrated with high-crystallinity β-Ga₂O₃ microwires (MWs), synthesized via chemical vapor deposition (CVD), to fabricate a self-powered deep-ultraviolet (DUV) photodetector. The device exhibited an ultra-low dark current of only 0.13 pA under a bias of 10 V, highlighting its superior noise suppression capability. More importantly, under 245 nm illumination at a bias of 0 V, the photodetector demonstrated a remarkable responsivity of 65 mA W⁻¹, which represents enhancements by factors of 48 and 4 compared with PEDOT:PSS/β-Ga₂O₃ MW and graphene/β-Ga₂O₃ MW heterostructures, respectively. In addition, the device achieved a high specific detectivity of ∼10¹² Jones. These outstanding photoresponse characteristics can be primarily attributed to the incorporation of graphene, which improves the conductivity of the PEDOT:PSS layer while simultaneously strengthening the built-in electric field at the heterojunction interface, thereby facilitating more efficient separation and transport of photogenerated carriers. Overall, this work demonstrates a promising strategy for designing organic–inorganic hybrid heterostructures and offers new insights into the development of high-performance, self-driven solar-blind photodetectors.