Hot-Electron Transistors for Terahertz Operation Based on Two-Dimensional Crystal Heterostructures

The authors explore the feasibility of ultrahigh-frequency devices by utilizing the unique features of two-dimensional (2D) crystals. These materials range from gapless semimetals to wide-band-gap insulators, and a number of them ($e.g.$ hexagonal boron nitride and transition metal dichalcogenides) can be integrated seamlessly with graphene, without causing defects, interfacial scattering centers, or degradation of properties. A detailed theoretical analysis indicates the potential for 2D crystal heterostructures that could process information at rates well over a terahertz--several times the current technological limit.