Explicit Model of Channel Charge, Backscattering, and Mobility for Graphene FET in Quasi-Ballistic Regime

摘要

Ballistic (collision free) and drift-diffusive (collision dominated) transport mechanisms are both present in graphene, and they together contribute in the current conduction in a graphene FET (GFET). In this paper, we propose an analytical drain current model based on ballistic (${n}_{B}$) and drift-diffusive (${n}_{D}$) charge densities, backscattering coefficient (${R}$), and quasi-ballistic mobility ($mu _{ext {eff}}$).${n}_{B}$is calculated using the McKelvey flux theory and${n}_{D}$using the surface potential approach. A closed-form analytical expression is derived for the backscattering coefficient, which is valid under both low and high electric field conditions. The effective quasi-ballistic mobility is obtained by considering both scattering-dominated and scattering free mobilities. The proposed model is well aligned with experimental data, in all regions of operation, for single- and double-gate GFETs.