Intrinsic high-frequency characteristics of graphene layers

The experimental results for the high-frequency transport characteristics (from 0.5 to 110 GHz) of graphene sheets are presented. Samples with graphene sheets of a different number of layers, as well as samples without graphene, were fabricated and compared by their room-temperature radio-frequency (RF) transmission properties. From RF two-port network experiments, the circuit parameters of resistance, inductance and capacitance were extracted using a lumped circuit model that consists of graphene, metal electrodes and contacts. Self-inductance was suppressed with decreasing number of layers, possibly due to minimized interlayer conduction or scattering. The graphene-electrode contact property shows dependence on the number of graphene layers. Our investigation may promote an understanding of the intrinsic graphene characteristics and graphene-electrode contact configuration in passive graphene devices for RF applications.