Resonant Plasmonic Terahertz Detection in Gated Graphene p - I - n Field-Effect Structures Enabled by Nonlinearity from Zener-Klein Tunneling

We show that resonant plasmonic detection dramatically increases the sensitivity of the terahertz detectors based on a gated graphene p-i-n (GPIN) field-effect transistor (FET) structure. In the proposed device, the gated p and n regions serve as the hole and electron reservoirs and the terahertz resonant plasma cavities. The current-voltage (I-V) characteristics are strongly nonlinear due to the Zener-Klein interband tunneling in the reverse-biased i region between the gates. The terahertz signal rectification by this region enables the terahertz detection. The resonant excitation of the hole and electron plasmonic oscillations results in a substantial increase in the terahertz detector responsivity at the signal frequency close to the plasma frequency and its harmonics. Because of the transit-time effects, the GPIN-FET response at the higher plasmonic modes could be stronger than for the fundamental mode. Our estimates predict the detector responsivity up to a few 105 V/W at room temperature, much larger than for other electronic terahertz detectors, such as Schottky diodes, p-n junctions, Si CMOS, and III-V and III-N HEMTs.