Enhancing Carrier Transport and Injection of Ga₂O₃ Deep-Ultraviolet Schottky Photodiode by Introducing Impurity Energy Level

In this letter, a Ti/Sn-Ga ₂ O ₃ /Ni Schottky photodiode device was achieved by a rarely-reported PECVD technology. Benefitting from the introduction of Sn impurity energy level, which provides extra paths for carriers’ generation and helps create a stronger built-in electric field to facilitate carriers’ separation, the carrier transport and injection efficiency of device are collaboratively enhanced. Under 254 nm deep-ultraviolet (DUV) light, the device displays an ultrahigh responsivity ( R ) of 3508A/W, outperforming the corresponding Ti/Ga ₂ O ₃ /Ni device (14.7 A/W) and many other Sn-doped Ga ₂ O ₃ photodetectors (PDs). Meanwhile, the device exhibits the low dark current of -6.6pA/4.79nA (~720 rectification ratio) under dark conditions, together with a remarkable external quantum efficiency of 1.72×10 ⁶ %, an outstanding detectivity of 4.9×10 ¹⁴ Jones at 5 V bias under DUV illumination. Furthermore, the device can operate in self-powered mode with an R of 100 mA/W as well, and this work demonstrates the huge potential of high-performance PECVD-grown elemental-doped Ga ₂ O ₃ film-based PDs.