Plasma excitations in field effect transistors for terahertz detection and emission

Resonant frequencies of the two-dimensional plasma in field effect transistors (FETs) increase with the reduction of the channel dimensions and can reach the THz range for nanometer size devices. Nonlinear properties of the electron plasma in the transistor channel can lead to the detection and emission of THz radiation. The excitation of plasma waves by sub-THz and THz radiation was experimentally demonstrated at cryogenic as well as at room temperatures. We present an overview of experimental results on THz detection by FETs discussing possibilities of improvement of their performance and application for THz room temperature imaging. We present also recent results on THz emission from GaN/AlGaN-based FETs. (C) 2010 Published by Elsevier Masson SAS on behalf of Academie des sciences.