Low-frequency noise in Terahertz plasmonic Field Effect Transistors

We discuss the thermal noise and the effect of input noise sources on the output noise of plasmonic Field Effect Transistors operating in a quasi-ballistic regime. The input noise strongly affects the output noise at large signals and when the detectors operate near the threshold, where the highest responsivity is reached. In the detection regime with a finite drain current, 1/f noise becomes dominant at low noise frequencies, and similar mechanisms determine the contribution of the input noise to the output noise. The effect of the input noise in the plasmonic THz detectors on their output noise analyzed based on the numerical solution of the hydrodynamic equations is in qualitative agreement with the analytical model but reveals the importance of plasmonic ringing even in the devices with the extracted mobilities of 3500 cm
²
/Vs with the gate length of 130 nm. These results are important for designing plasmonic sensors using the frequency dependencies of the low frequency output noise for identifying different gas and liquid substances.