Résumé
We report on the detection of the sub-THz and THz radiation by silicon FETs and on the voltage tunable emission of terahertz radiation from InGaAs/AlInAs HEMTs with nanoscale gate lengths. The observed photo-response is in agreement with the predictions of the plasma wave response theory. The spectrum of the emitted signal has two peaks. The lower peak is interpreted as resulting from the Dyakonov - Shur instability of the gated two dimensional electron fluid. The emission measurements in a magnetic field show that the threshold voltage remains close to the transistor saturation voltage that increases with magnetic field due to geometric magnetoresistance.