Plasma Oscillations in Nanotransistors: Application to THz Radiations Detection and Generation

Abstract

By means of a numerical hydrodynamic model, we consider the mechanism of collective plasma oscillations in a field-effect transistor channel under different excitations and biasing conditions. First, we consider the case of a device externally-excited by a harmonic optical beating or an electronic excitation under constant current condition at the drain. Both situations exhibit sharp resonances related to the first odd plasma modes illustrating the possibility of using the HEMT as a terahertz photomixer or detector. Then, we demonstrate that the frequencies, amplitudes and quality factors of the resonances can be strongly modified by varying the drain biasing condition from current-to voltage-driven operation.

Investigation of high-frequency small-signal characteristics of FETs/HEMTs

“…Here, as a detecting signal any physical action able to excite in a resonant way the 2D plasma oscillations in the gated part of the FET/HEMT channel can be used. For example, the most often discussed cases are the direct electrical action [35] or the photo-excitation of electron-hole pairs in the FET/HEMT channel modulated by the beating frequency of two IR lasers in the THz frequency range (see, e.g., [14][15][16][17][18][19][20][21][22]35] and references therein).…”