Self-powered PEDOT:PSS/Sn:α-Ga₂O₃ heterojunction UV photodetector via organic/inorganic hybrid ink engineering

Abstract In this work, a PEDOT:PSS/Sn: α -Ga 2 O 3 hybrid heterojunction diode (HJD) photodetector was fabricated by spin-coating highly conductive PEDOT:PSS aqueous solution on the mist chemical vapor deposition (Mist-CVD) grown Sn: α -Ga 2 O 3 film. This approach provides a facile and low-cost p-PEDOT:PSS/n-Sn: α -Ga 2 O 3 spin-coating method that facilitates self-powering performance through p−n junction formation. A typical type-Ⅰ heterojunction is formed at the interface of Sn: α -Ga 2 O 3 film and PEDOT:PSS, and contributes to a significant photovoltaic effect with an open-circuit voltage ( V oc ) of 0.4 V under the 254 nm ultraviolet (UV) light. When operating in self-powered mode, the HJD exhibits excellent photo-response performance including an outstanding photo-current of 10.9 nA, a rapid rise/decay time of 0.38/0.28 s, and a large on/off ratio of 91.2. Additionally, the HJD also possesses excellent photo-detection performance with a high responsivity of 5.61 mA/W and a good detectivity of 1.15 × 10 11 Jones at 0 V bias under 254 nm UV light illumination. Overall, this work may explore the potential range of self-powered and high-performance UV photodetectors.