ABSTRACT
In this chapter, the authors study instability of plasmons in a dual-grating-gate graphene field-effect transistor induced by dc current injection using self-consistent simulations with the Boltzmann equation. They show the gate-length dependence of the plasmon frequency and the total growth rate extracted from the simulations. Electronic, hydrodynamic, and electromagnetic properties of two-dimensional plasmons in channels of field-effect transistors have been investigated extensively for their utilization to terahertz devices. Plasmons in graphene have then attracted much attention owning to its gapless energy spectrum and massless carriers. Depending on the length of the low-concentration region and the electron velocity, it interferes with plasmons in the high-concentration region either constructively or destructively. The plasmon frequency is again determined by the geometrical factors in the high-concentration region and the gate voltage. Distinct fundamental modes can be obtained with certain sets of parameters, and the frequency and total growth rate can be easily extracted.
