Radio Frequency Field-Induced Enhancement of Detection Sensitivity in Silicon Nanowire Sensors

TL;DR

This paper introduces a novel biosensing method using radiofrequency-induced flexoelectric resonance in silicon nanowires, significantly enhancing detection sensitivity in physiological fluids by overcoming Debye screening.

Contribution

It demonstrates a new sensing approach leveraging flexoelectric resonance to improve biomarker detection sensitivity in high-ionic-strength environments.

Findings

Order-of-magnitude sensitivity improvement with RF modulation

62% conductance increase versus 30% without RF

Reduced Debye screening enabling direct detection

Abstract

Sensitive biomarker detection in physiological fluids is often limited by Debye screening, which suppresses electrostatic signals at sensor surfaces. Here we report a sensing approach based on flexoelectric resonance in silicon nanowire field-effect transistors. An applied radiofrequency field induces strain gradients in the nanowires, generating flexoelectric polarization that is amplified at resonant frequencies. This effect enhances the sensitivity of conductance measurements to small surface charge variations associated with biomolecular binding. Using C-reactive protein as a model biomarker, we observe an order-of-magnitude improvement in detection sensitivity compared to conventional operation, with a 62% conductance increase versus 30% without radiofrequency modulation. The high-frequency field also perturbs the electrical double layer, reducing Debye screening in high-ionic-strength environments. These combined effects enable direct biomarker detection without sample dilution. This work establishes flexoelectric resonance as a general strategy for improving nanoscale biosensing performance in physiologically relevant conditions.