A Silicon Nanowire Ion-Sensitive Field-Effect-Transistor with elementary charge sensitivity

TL;DR

This study demonstrates that silicon nanowire FETs can achieve charge sensitivity below the elementary charge, with low noise levels unaffected by ionic strength, enabling precise molecular detection.

Contribution

The paper reveals that dielectric polarization noise dominates low-frequency noise in liquid-gated SiNW-FETs, achieving charge sensitivity below elementary charge levels.

Findings

Charge noise spectral density of 1.6x10^-2 e/√Hz at 10 Hz

Minimal effect of electrolyte ionic strength on device noise

Dielectric polarization noise identified as primary noise source

Abstract

We investigate the mechanisms responsible for the low-frequency noise in liquid-gated nano-scale silicon nanowire field-effect transistors (SiNW-FETs) and show that the charge-noise level is lower than elementary charge. Our measurements also show that ionic strength of the surrounding electrolyte has a minimal effect on the overall noise. Dielectric polarization noise seems to be at the origin of the 1/f noise in our devices. The estimated spectral density of charge noise Sq = 1.6x10-2 e/sqr(Hz) at 10 Hz opens the door to metrological studies with these SiNW-FETs for the electrical detection of a small number of molecules.