▎ 摘 要
Graphene, which is mechanically flexible, electrically conductively, and optically nearly transparent, is a promising contact material in semiconductor devices such as solar cells and touch screen sensors. We present a method of obtaining the barrier height and transport properties of graphene-silicon contacts by self-consistently solving the Poisson equation and carrier transport equation. It is found that the contact barrier height is sensitive to the doping density of silicon and can be modulated by gating, in contrast to conventional metal-semiconductor contacts. Despite of being a continuous film, the contact resistance of a monolayer graphene to silicon can be modulated by orders of magnitude by using a bottom gate. The modulation of the contact resistance decreases significantly as the number of graphene layers increases and becomes negligible when the number of the graphene layers is larger than about 6. The results indicate the unique properties of graphene-semiconductor contacts. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759152]