Abstract
Two-dimensional (2-D) electron plasma in a submicron channel of a high-electron mobility transistor (HEMT) is excited by interband photoexcitation, resulting in performing the photomixing function. The injected photoelectrons modulate the total 2-D electron density, affecting the plasma resonant properties. The modulation depth of the density of 2-D electrons by the photoelectrons deeply relates to the resonant intensity and fr. This effect was modeled analytically in the 2-D plasma hydrodynamic equation. In order to validate the analytical calculation, the plasma-wave resonance was experimentally observed for a 0.15-µm gate-length InGaP/InGaAs/GaAs pseudomorphic HEMT in the terahertz range. At the modulation depth of 30%, the resonance was clearly observed with a double peak (the peak at 1.9/5.8 THz corresponding to the fundamental/third harmonic resonance). The resonant frequencies slightly shifted downward and the intensity attenuated with decreasing the modulation depth. Observed resonant frequencies support the analytical calculation.