A Fitting Model for Asymmetric $I$ – $V$ Characteristics of Graphene FETs for Extraction of Intrinsic Mobilities

A fitting model is developed for accounting the asymmetric ambipolarities in the I-V characteristics of graphene FETs (G-FETs) with doped channels, originating from the thermionic emission and interband tunneling at the junctions between the gated and access regions. Using the model, the gate-voltage-dependent intrinsic mobility as well as other intrinsic and extrinsic device parameters can be extracted. We apply it to a top-gated G-FET with a graphene channel grown on a SiC substrate and with SiN gate dielectric that we reported previously, and we demonstrate that it can excellently fit its asymmetric I-V characteristic.