Schottky graphene/silicon photodetectors based on internal photoemission effect

In this paper, the design of a graphene/silicon photodetector working at both 1.55 μm and room temperature is reported. The device is a Schottky diode and the absorption mechanism is based on the internal photoemission effect. In order to quantify the performance of the photodetector, quantum efficiency, bandwidth and dark current density are numerically calculated. Performance comparison between our proposed device and typical metal/silicon Schottky photodetectors is reported. Graphene/silicon devices show an efficiency as high as 39.5% at 1300 nm and 34.9% at 1550 nm but, unfortunately, a high dark current density of 0.8 nA/μm². Finally, a bandwidth of about 7.6 GHz can be estimated.