This paper reports on the characteristics of the plasmonic phenomena in diamond FET devices at THz frequencies. We present a detailed numerical study of the terahertz resonant response of n-diamond TeraFETs as a function of temperature and channel length, demonstrate their potential for emerging terahertz applications, and compare their performance with that for p-diamond devices. The results show that short channel n-diamond TeraFETs exhibit a resonant response at room and cryogenic temperatures. We also report on the impact of the amplitude of the impinged THz signal and gate-to-channel separation on the induced voltage response. In our analysis, we have accounted for the effect of the viscosity of the electron fluid in the channel which is one of the major contributors to the damping of the plasma waves.
