Gate Tuning of High-Performance InSe-Based Photodetectors Using Graphene Electrodes

In order to increase the response speed of the InSe-based photodetector with high photoresponsivity, graphene is used as the transparent electrodes to modify the difference of the work function between the electrodes and the InSe. As expected, the response speed of InSe/graphene photodetectors is down to 120 μs, which is about 40 times faster than that of an InSe/metal device. It can also be tuned by the back-gate voltage from 310 μs down to 100 μs. With the high response speed, the photoresponsivity can reach as high as 60 A W^-1 simultaneously. Meanwhile the InSe/graphene photodetectors possess a broad spectral range at 400-1000 nm. The design of 2D crystal/graphene electrical contacts can be important for high-performance optoelectronic devices.