Modeling of the excitation of terahertz plasma oscillations in a HEMT by ultrashort optical pulses

Device models for the HEMT-based THz source are developed: an all-analytical model and a model in which the electron systems in the channel is considered analytically in the linear approximation, whereas the transport of the photogenerated electrons and holes is treated invoking an ensemble Monte Carlo particle simulation. Using these models, the frequency-dependent currents and device responsivity as functions of the structural parameters, gate voltage, and energy of the absorbed optical photons are calculated. An example of the dependences calculated for HEMTs with the fundamental plasma frequency f_P = 1 THz and different values of the electron mobility μ in the channel is performed.