Thickness-Dependent Electrical Transport Properties of Graphene

We have studied the resistance of a graphene sample as a function of flake thickness. The graphene sample thickness ranged from sub-nanometer (similar to 0.65 nm) to few tens of nanometer (similar to 50 nnn) with active channel area in several mu m(2). The electrical transport phenomenon of the fabricated graphene device shows a metallic to semiconductor transition with respect to sample thickness. The c-axis characteristic (semiconducting to metallic) was observed only in few layer graphene. The obtained result clearly indicates that the resistance of ideal, defect-free graphene samples is sensitive to the number of graphene layers.