High Responsivity and High Rejection Ratio of Self-Powered Solar-Blind Ultraviolet Photodetector Based on PEDOT:PSS/β-Ga₂O₃ Organic/Inorganic p-n Junction

A high responsivity self-powered solar-blind deep UV (DUV) photodetector with high rejection ratio was proposed based on inorganic/organic hybrid p-n junction. Owing to the high crystallized β-Ga₂O₃ and excellent transparent conductive polymer PEDOT:PSS, the device exhibited ultrahigh responsivity of 2.6 A/W at 245 nm with a sharp cutoff wavelength at 255 nm without any power supply. The responsivity is much larger than that of previous solar-blind DUV photodetectors. Moreover, the device exhibited an ultrahigh solar-blind/UV rejection ratio (R_{245 nm}/R_{280 nm}) of 10³, which is two orders of magnitude larger than the average value reported in Ga₂O₃-based solar-blind photodetectors. In addition, the photodetector shows a narrow bandpass response of only 17 nm in width. This work might be of great value in developing a high wavelength selective DUV photodetector with respect to low cost for future energy-efficient photoelectric devices.