External excitation of hybrid plasma resonances in a gated semiconductor slab: An analytical study

We derive at first-order the carrier and velocity conservation equations and a pseudo-2D (P2D) Poisson equation in order to obtain an analytical model suitable for the study of the optical and electrical excitations of the plasma modes in a gated semiconductor channel of arbitrary thickness. We calculate the dispersion relation of the plasma waves appearing in the channel and the frequencies of the eigen modes for different boundary conditions (BCs). Then, we obtain and comment different THz-range frequency responses to an uniform optical beating or to an electrical excitation applied on the gate or the drain contacts. The effects of the different stimulations and boundary conditions are compared, and the responses, characterized by sharp resonances in the THz range, are interpreted as the sum of the contribution of the different hybrid plasma modes excited in the slab.