High-performance β-Ga 2 O 3 -based solar-blind photodetector with ultralow dark current and fast photoresponse for deep-ultraviolet communication

Abstract

Solar-blind deep-ultraviolet communication (SDUC) presents a promising candidate for use in short-range military communications. Solar-blind photodetectors (PDs) form up the core component of the SDUC system’s receiving signal. In this study, an easy-to-integrate metal-semiconductor-metal (MSM)-type solar-blind PD is successfully fabricated based on the β-Ga 2 O 3 film deposited on c-plane sapphire substrates by low-cost radio-frequency magnetron sputtering. The fabricated device exhibits a high responsivity of 1.93 A W −1 , a remarkable detectivity of 6.53×10 13 Jones, and a considerable photo-to-dark current ratio of 3.58×10 5 . Most importantly, the device shows an extremely low dark current of 82 fA and an ultrafast response speed of 11/240 µs; one of the most ultra-high performances ever reported for β-Ga 2 O 3 solar-blind PDs. In addition, it is the first time that a high-performance β-Ga 2 O 3 -based PD that is integrated into a self-made SDUC system as a signal receiver is demonstrated to transmit ASCII codes with such high accuracy and a data rate of 10 kbps. The results reported in this work serve as proof-of-concept for future applications of β-Ga 2 O 3 solar-blind deep-ultraviolet photodetectors in secure communications.