Abstract
Light loss is one of the main factors affecting the quantum efficiency of photodetectors. Many researchers have attempted to use various methods to improve the quantum efficiency of silicon-based photodetectors. Herein, we designed highly anti-reflective silicon nanometer truncated cone arrays (Si NTCAs) as a light-trapping layer in combination with graphene to construct a high-performance graphene/Si NTCAs photodetector. This heterojunction structure overcomes the weak light absorption and severe surface recombination in traditional silicon-based photodetectors. At the same time, graphene can be used both as a broad-spectrum absorption layer and as a transparent electrode to improve the response speed of heterojunction devices. Due to these two mechanisms, this photodetector had a high quantum efficiency of 97% at a wavelength of 780 nm and a short rise/fall time of 60/105µs. This device design promotes the development of silicon-based photodetectors and provides new possibilities for integrated photoelectric systems.
Highlights
The photodetector can work under zero bias with excellent photodetection performance
nanometer truncated cone arrays (NTCAs) device was in the order of microseconds, shorter than that of most other van der Waals (vdWs) heterojunction photodetectors based on 2D layered materials
The morphology of the Si NTCAs and graphene/Si NTCAs was obtained by scanning electron microscopy (SEM; SU1510)
Summary
Compared with planar Si or Si nanopillars, NTCAs further enhance light absorption, confirmed by both simulation and experimental results in this study On this basis, graphene was transferred as a transparent upper electrode and formed a heterojunction with silicon to prepare a high quantum efficiency photodetector. The response time (rise/fall time of 60/150 μs) of the constructed graphene/Si. NTCAs device was in the order of microseconds, shorter than that of most other vdWs heterojunction photodetectors based on 2D layered materials. NTCAs device was in the order of microseconds, shorter than that of most other vdWs heterojunction photodetectors based on 2D layered materials This graphene/Si NTCAs device reveals unique opportunities for future high quantum efficiency, broadband, and high-speed photodetectors
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