Refine treatment of plasmon mediated photoconductivity resonances in a grid-gated double-quantum-well field-effect transistor

Recent observations of THz photoconductivity in a double-quantum-well (DQW) field-effect transistor (FET) with a periodic metal-grid gate indicate that the presence of an asymmetric DQW is essential to produce a large photoresponse. The strongest THz photoresponse occurs when the upper QW (nearest to the gate) is fully depleted under metal portions of the grating gate, while the lower one remains connected, but with a laterally modulated electron density. The positions and strengths of the resonant peaks in the photoresponse are controlled by both the voltage applied to the gate and the period of the grating gate. In this paper, we exhibit a correlation between magnitudes of the plasmon absorption resonances and resonant changes in photoconductance of the DQW-FET channel.