Terahertz responsivity of field effect transistors versus their static channel conductivity and loading effects

Abstract

We study the broadband photovoltaic response of field effect transistors on terahertz radiation. A simple physical analytical model of the response is developed. It is based on plasma density perturbation in the transistor channel by the incoming terahertz radiation. The model shows how the non-resonant detection signal is related to static (dc) transistor characteristics. We analyze loading effects related to capacitive, inductive, and resistive coupling of the detector to the read-out circuit as a function of modulation frequencies and loading resistors. As we show, the proposed physical model completed by loading effects fully describes the experimental results on the non-resonant sub-terahertz detection by all studied III-V (GaAs, GaN) and silicon based transistors. Field effect transistors were recently proposed as the best terahertz detecting pixels for fabrication of low cost focal plane arrays for terahertz imaging. This article gives prospects for electrical simulation of these transistors and their optimal integration in the focal plane arrays.

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AlGaN/GaN HEMT’s photoresponse to high intensity THz radiation

“…We simulated the photoresponse at 292 GHz for channels T1 and T2 separately, as well as for two channels in parallel (T) taking into account the dependence L o (U g ) and loading conditions [10]. Results are presented in Fig.…”