Ballistic Injection Terahertz Plasma Instability in Graphene n⁺–i–n–n⁺ Field-Effect Transistors and Lateral Diodes

The operation of the graphene n⁺–i–n–n⁺ field-effect transistors (GFETs) and lateral diodes (GLDs) with the injection of ballistic electrons into the n-region is analyzed. The momentum transfer of the injected ballistic electrons can lead to an effective Coulomb drag of the quasiequilibrium electrons in the n-region and the plasma instability in the GFETs and GLDs. The instability enables the generation of terahertz radiation. The obtained results can be used for the optimization of the structures under consideration for different devices, in particular, terahertz emitters.