Photo-Induced Doping in Graphene/Silicon Heterostructures

Photoinduced doping in graphene and its related heterostructures has drawn much interest as one of the possible ways to control the electronic properties of graphene. In this paper, we report that graphene/silicon (Gr/Si) heterostructures are an effective configuration for photoinduced doping in graphene. Raman spectroscopy, electrical and photoelectrical measurements are used to characterize the photoinduced doping effect. The results demonstrate that the graphene in the Gr/Si heterostructure is p-doped by light irradiation, and the doping effect can be controlled by varying the irradiation time. For the electrical properties of the Gr/Si Schottky junction, the photoinduced doping effect reduces the barrier height and series resistance but enhances the ideality factor. For the photovoltaic properties, the doping strengthens the open-circuit voltage, short-circuit current, fill factor, and conversion efficiency. The work should be helpful on developing effective ways for graphene doping and in depth understanding and better use of Gr/Si Schottky junctions for electronics and optoelectronics.