Graphene Schottky Varactor Diodes for High-Performance Photodetection

Over the past decade graphene devices have inspired the progress of future electronic and optoelectronic technologies. The unique combination of fast carrier dynamics and intrinsic quantum capacitance of graphene is a fertile ground for implementing novel device architectures. Here, we report on a novel device architecture comprising graphene Schottky diode varactors and assess the potential applications of this type of new device in optoelectronics. We show that graphene varactor diodes exhibit significant advantages compared with existing graphene photodetectors including elimination of high dark currents and enhancement of the external quantum efficiency (EQE). Our devices demonstrate a large photoconductive gain and EQE of up to 37%, fast photoresponse, and low leakage currents at room temperature.