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

In this letter, a Ti/Sn-Ga2O3/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/Ga2O3/Ni device (14.7 A/W) and many other Sn-doped Ga2O3 photodetectors (PDs). Meanwhile, the device exhibits the low dark current of -6.6pA/4.79nA (similar to 720 rectification ratio) under dark conditions, together with a remarkable external quantum efficiency of 1.72 x 10(6)%, an outstanding detectivity of 4.9 x 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 Ga2O3 film-based PDs.