Plasma Instability in Graphene Field-Effect Transistors with a Shifted Gate

We present detailed numerical analysis of the Dyakonov–Shur (DS) plasma instability in a DC biased graphene field-effect transistor (FET) with the gate shifted with respect to the middle of the transistor conducting channel. We show that the geometric asymmetry is sufficient to trigger the DS instability in the two-dimensional electron gas in the transistor channel. We demonstrate sustained plasma oscillations in the instability end point and analyze the properties of these oscillations for different positions of the gate and at different values of other physical and geometric FET parameters. The obtained results show the possibility of designing a tunable on-chip source of terahertz electromagnetic radiation based on the graphene FET with shifted gate.