THz detection with epitaxial graphene field effect transistors on silicon carbide

TL;DR

This paper demonstrates room temperature THz detection using epitaxial graphene FETs on silicon carbide, revealing dual detection mechanisms and potential for large-area imaging despite the need for improved responsivity.

Contribution

It introduces a novel THz detection method with epitaxial graphene FETs, identifying plasma wave and thermoelectric mechanisms and analyzing their combined effects.

Findings

Detection achieved at room temperature.

Both plasma wave and thermoelectric effects contribute.

Plasmonic detection dominates under certain conditions.

Abstract

We report on room temperature THz detection by means of antenna-coupled field effect transistors fabricated by using epitaxial graphene grown on silicon carbide substrate. Two independent detection mechanisms are found: plasma wave assisted-detection and thermoelectric effect, which is ascribed to the presence of junctions along the FET channel. The superposition of the calculated functional dependence of both the plasmonic and thermoelectric photovoltages on the gate bias qualitatively well reproduces the measured photovoltages. Additionally, the sign reversal of the measured photovoltage demonstrates the stronger contribution of the plasmonic detection compared to the thermoelectric mechanism. Although responsivity improvement is necessary, these results demonstrate that plasmonic detectors fabricated by epitaxial graphene on silicon carbide are potential candidates for fast large area imaging of macroscopic samples.