Features of the gate coupling effect in liquid-gated Si nanowire FETs

We present results of a comprehensive study of the liquid-back gate coupling effect in our Si nanowire (NW) field-effect transistor (FET) structures using noise spectroscopy in different operation modes, including variable back-gate voltage. The constant channel resistance regime was used for measurements of the transport and noise properties of the liquid-gated Si NW FETs and simulations using Sentaurus TCAD software to improve our understanding of the coupling effect phenomena. The concentration profiles were simulated for different liquid- and back-gate voltages, which correspond to the experimental working points. The noise spectra were studied while tuning the position of the conducting channel in the liquid-gated Si NW FET. Results demonstrate that the dominant flicker noise mechanism in such structures is the number fluctuations due to the localization of the conducting channel near the dielectric layer of the liquid gate.