Resonant plasmonic terahertz detection in graphene split-gate field-effect transistors with lateral p-n junctions

TL;DR

This paper proposes and models resonant terahertz detectors based on graphene split-gate FETs with lateral p-n junctions, demonstrating high responsivity and tunable plasmonic resonances for improved THz detection.

Contribution

It introduces a novel device model for graphene-based THz detectors with split gates and lateral p-n junctions, highlighting their high responsivity and tunability.

Findings

Detectors exhibit high voltage responsivity near plasmonic resonance frequencies.

Resonant response is more pronounced in perforated graphene (PGL-FET) due to lower junction conductance.

Current rectification mechanisms differ: tunneling in GL-FET and thermionic in PGL-FET.

Abstract

We evaluate the proposed resonant terahertz (THz) detectors on the base of field-effect transistors (FETs) with split gates, electrically induced lateral p-n junctions, uniform graphene layer (GL) or perforated (in the p-n junction depletion region) graphene layer (PGL) channel. The perforated depletion region forms an array of the nanoconstions or nanoribbons creating the barriers for the holes and electrons. The operation of the GL-FET- and PGL-FET detectors is associated with the rectification of the ac current across the lateral p-n junction enhanced by the excitation of bound plasmonic oscillations in in the p- and n-sections of the channel. Using the developed device model, we find the GL-FET and PGL-FET-detectors characteristics. These detectors can exhibit very high voltage responsivity at the THz radiation frequencies close to the frequencies of the plasmonic resonances. These frequencies can be effectively voltage tuned. We show that in PL-FET-detectors the dominant mechanism of the current rectification is due to the tunneling nonlinearity, whereas in PGL-FET-detector the current rectification is primarily associated with the thermionic processes. Due to much lower p-n junction conductance in the PGL-FET-detectors, their resonant response can be substantially more pronounced than in the GL-FET-detectors corresponding to fairly high detector responsivity.