Review of deep ultraviolet photodetector based on gallium oxide

Ultraviolet (UV) photodetectors (PDs) have drawn great attention in recent years due to their potential application in civil and military fields. Because of its ultrawide bandgap, low cost, strong radiation hardness, and high thermal and chemical stability with high visible-light transparency, Ga2O3 is regarded as the most promising candidate for UV detection. Furthermore, the bandgap of Ga2O3 is as high as 4.7-4.9 eV, directly corresponding to the solar-blind UV detection band with wavelength less than 280 nm. There is no need of doping in Ga2O3 to tune its bandgap, compared to AlGaN, MgZnO, etc, thereby avoiding alloy composition fluctuations and phase separation. At present, solar-blind Ga2O3 photodetectors based on single crystal or amorphous Ga2O3 are mainly focused on metal-semiconductor-metal and Schottky photodiodes. In this work, the recent achievements of Ga2O3 photodetectors are systematically reviewed. The characteristics and performances of different photodetector structures based on single crystal Ga2O3 and amorphous Ga2O3 thin film are analyzed and compared. Finally, the prospects of Ga2O3 UV photodetectors are forecast.