Field Effect Transistors for Terahertz Detection: Physics and First Imaging Applications

TL;DR

This paper reviews the physics of field effect transistors (FETs) for terahertz detection, highlighting their resonant plasma properties at cryogenic temperatures and broadband detection capabilities at room temperature, with applications in THz imaging.

Contribution

It provides the first comprehensive overview of FET-based THz detection physics and demonstrates their potential in THz imaging applications.

Findings

Resonant plasma frequencies in FETs reach THz range for sub-micron channels.

FETs operate as broadband THz detectors at room temperature.

Experimental and theoretical results support FETs' use in THz imaging.

Abstract

Resonant frequencies of the two-dimensional plasma in FETs increase with the reduction of the channel dimensions and can reach the THz range for sub-micron gate lengths. Nonlinear properties of the electron plasma in the transistor channel can be used for the detection and mixing of THz frequencies. At cryogenic temperatures resonant and gate voltage tunable detection related to plasma waves resonances, is observed. At room temperature, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector. We present the main theoretical and experimental results on THz detection by FETs in the context of their possible application for THz imaging.