A Fitting Model for Asymmetric I-V Characteristics of Graphene   Field-Effect Transistors for Extraction of Intrinsic Mobilities
  A fitting model is developed for accounting the asymmetric ambipolarities in the I-V characteristics of graphene field-effect transistors (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. 
Akira Satou, Gen Tamamushi, Kenta Sugawara, Junki Mitsushio, Victor   Ryzhii, and Taiichi Otsuji
cond-mat.mes-hall