Generation and detection of Terahertz radiation by Field Effect Transistors

TL;DR

This paper reviews how field effect transistors can generate and detect Terahertz radiation through plasma oscillations, with potential for high-frequency applications and broadband detection.

Contribution

It highlights the physical mechanisms enabling FETs to operate in the THz range, including plasma wave dynamics and their dependence on device dimensions and mobility.

Findings

Resonant plasma oscillations reach THz frequencies in sub-micron FETs.

High mobility enables plasma wave dominance at THz frequencies.

Overdamped plasma oscillations allow FETs to function as broadband THz detectors.

Abstract

This is a brief overview of the main physical ideas for application of field effect transistors for generation and detection of TeraHertz radiation. Resonant frequencies of the two-dimensional plasma oscillations in FETs increase with the reduction of the channel dimensions and reach the THz range for sub-micron gate lengths. When the mobility is high enough, the dynamics of a short channel FET at THz frequencies is dominated by plasma waves. This may result, on the one hand, in a spontaneous generation of plasma waves by a dc current and on the other hand, in a resonant response to the incoming radiation. In the opposite case, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector.