TeraHertz Emission and Noise Spectra in HEMTs

In this work we investigate, by means of Monte Carlo simulations, the physics of the recently observed emission of THz radiation at low temperature (4.2 K) from InGaAs/InAlAs lattice‐matched high electron mobility transistors, HEMTs. The spectrum of the emitted signal consists of two maxima; the one at lower frequency (around 1 THz) is sensitive to UDS and UGS, while the higher frequency peak (around 5 THz) is not. The gate current noise spectra obtained with room‐temperature Monte Carlo simulations of similar HEMTs also show those features, although some quantitative discrepancies arise from the different temperature conditions. The signature of plasma oscillations is known to appear in the current noise spectrum, producing peaks appearing at very high frequencies. On the other hand, peaks at frequencies around 1 THz can be associated with the formation of Gunn domains within the transistors. Therefore, the analysis of the noise spectra of these devices can provide useful information that can help to und...