▎ 摘　　要

We obtain the output and transfer characteristics of graphene field-effect transistors by using the charge-control model for the current, based on the solution of the Boltzmann equation in the field-dependent relaxation time approximation. Closed expressions for the conductance, transconductance, and saturation voltage are derived. We found good agreement with the experimental data of Meric et al. [Nat. Nanotechnol. vol. 3, p. 684, 2008] without assuming carrier density-dependent velocity saturation.