Explicit Drain Current, Charge and Capacitance Model of Graphene Field-Effect Transistors

This paper presents a compact physics-based model of the drain current, charge, and capacitance of graphene field-effect transistors, which is of relevance for the exploration of dc, ac, and transient behavior of graphene-based circuits. The physical framework is a field-effect model and drift-diffusion carrier transport incorporating saturation velocity effects. First, an explicit model has been derived for the drain current. Using it as a basis, explicit closed-form expressions for the charge and capacitances based on the Ward-Dutton partition scheme were derived, covering continuously all the operation regions. The model is of special interest for analog and radio-frequency applications where bandgap engineering of graphene is not needed.