High-performance flexible WSe2 flake photodetector with broadband detection capability

Abstract

In this age of interconnection, photodetectors based on two-dimensional materials have been widely used in wearable physiological monitoring systems and wireless sensor networks. Hence, this paper proposes a novel WSe2 flake photodetector with a metal–semiconductor–metal structure. The photodetector achieved a high responsivity (Ri) of 2.46 A/W under the condition of an external bias voltage at 650 nm as well as an ultra-high detectivity (D*) of 0.76 × 1011 Jones. The photodetector overcomes the shortcomings of traditional photoelectric detectors with large dark currents. A small dark current of ∼1 nA was obtained, which also creates an opportunity for future high-performance photoelectric devices. After 500 bending cycles, the current and dark current of the device decreased only by 1.7%. Additionally, a self-built test platform indicated that the test device has a device response time of up to 6.51 ms, which creates an opportunity for the high-speed corresponding photoelectric devices based on WSe2 flakes in the future.