Transport phenomena in liquid-gated Si nanowire FETs for biosensing applications

We review transport and noise properties of liquid-gated Si nanowire field-effect transistor structures designed and fabricated for biosensing applications, aiming to study the response at the level of a single molecule or single neuron. It is shown that the characteristic capture time of a single trap, determined from random telegraph signal noise, contains important information about surface potential changes, with enhanced sensitivity compared to standard measurements of the drain current´s dependence on the pH concentration of the solution. The gate coupling effect determined was used to improve the signal-to-noise ratio: an important characteristic to register small signals from neuronal activity.