Boltzmann transport equation‐based semi‐classical drain current model for bilayer GFET including scattering effects

Abstract

In this study, a drain current model of bilayer graphene field-effect transistor (GFET) has been developed. The Boltzmann transport approach is considered to develop this model including the scattering effects. The effects of optical phonon scattering, acoustic phonon scattering and carrier-carrier scattering have been included. The effective voltages at top and back gates induce net mobile sheet charge density in graphene channel. Mobile sheet charge density helps to determine the quantum capacitance. Channel potential is derived from equivalent circuit. The electronic transport phenomena of carriers in channel are explained for the contribution of both electron and hole charge density. Finally, the expression of drain current is determined using the Boltzmann transport equation under non-equilibrium condition. Contact resistances at source and drain regions are considered to determine the accurate drain current. The small signal parameters of GFET are determined from drain current and net charge density, and finally using these parameters the authors have calculated the cut-off frequency of the model. We validate the model with several contemporary experimental results. Utilising the model, we have also explored the impact of back-gate bias, top-gate bias and channel length on the device characteristics.