Resonant THz detection by periodic multi-gate plasmonic FETs

TL;DR

This paper demonstrates that a periodic multi-gate structure in THz plasmonic FETs significantly enhances detection sensitivity by creating harmonic responses, with the potential to double the response amplitude compared to uniform devices.

Contribution

The study introduces a novel multi-gate design in THz FETs that leverages spatial non-uniformity to improve detection sensitivity and provides a mapping method to optimize device parameters.

Findings

Response amplitude can be increased up to 100% in enhanced regions.

The distribution of response regions depends on the number of gate sections.

A mapping of response amplitude helps identify optimal operating conditions.

Abstract

We show that a periodic multi-grated-gate structure can be applied to THz plasmonic FETs (TeraFETs) to improve the THz detection sensitivity. The introduction of spatial non-uniformity by separated gate sections creates regions with distinct carrier concentrations and velocities, giving rise to harmonic behaviors. The resulting frequency spectrum of DC voltage response is composed of enhanced and suppressed regions. In the enhanced region, the amplitude of response voltage can be enlarged up to 100% compared to that in a uniform channel device. The distribution pattern of those regions is directly related to the number of gate sections (Ns). A mapping of response amplitude in an Ns-frequency scale is created, which helps distinguish enhanced/suppressed regions and locate optimal operating parameters.