A High-performance Self-powered Ultraviolet Photodetector with Spiro-MeOTAD/N-doped Ga2O3 heterojunction

Gallium oxide (Ga₂O₃) based ultraviolet (UV) photodetectors have broad application prospects in military and civilian fields due to their strong radiation resistance, insignificant background interference, and low false alarm rate. However, during the growth process of Ga₂O₃ materials, oxygen vacancies (Vo) are inevitably generated, resulting in a slow response speed and persistent photoconductivity (PPC) effect for the detector. Here, the plasma enhanced chemical vapor deposition method is employed to introduce nitrogen doping, successfully reducing the Vo concentration of Ga₂O₃ film and significantly inhibiting the PPC effect. Based on it, a type-Ⅱ band arrangement heterojunction of Spiro-MeOTAD/N-doped Ga₂O₃ is constructed, which can effectively separate photogenerated carriers without additional bias to achieve self-powered performance. Concretely, this device operates a photo-to-dark current ratio of 2160 and a rapid response time of around 0.112 s/0.163 s at 0 V. The excellent performances indicate that the heterojunction is a promising photodetector due to its self-powered, fast response, and high-sensitivity detection for UV signals.