Piezoresistance characterization of silicon nanowires in uniaxial and isostatic pressure variation

TL;DR

This study investigates the piezoresistance properties of silicon nanowire arrays under uniaxial and isostatic pressures, demonstrating their potential as sensitive pressure sensors with high stability and resolution.

Contribution

It provides a detailed analysis of the piezoresistance response of interconnected silicon nanowire arrays under different pressure conditions, highlighting their enhanced mechanical stability and sensing capabilities.

Findings

Achieved pressure sensing resolution of about 1 mbar.

Observed over two orders of magnitude resistance change under isostatic pressure.

Demonstrated high repeatability and stability across multiple samples.

Abstract

Silicon nanowires (SiNWs) are known to exhibit large piezoresistance (PZR) effect, making it suitable for various sensing applications. Here, we report the results of a PZR investigation on randomly distributed and interconnected vertical silicon nanowire arrays as a pressure sensor. The samples were produced from p-type (100) Si wafers using a silver catalysed top-down etching process. The piezoresistance response of these SiNW arrays was analysed by measuring their I-V characteristics under applied uniaxial as well as isostatic pressure. The interconnected SiNWs exhibit increased mechanical stability in comparison with separated or periodic nanowires. The repeatability of the fabrication process and statistical distribution of measurements were also tested on several samples from different batches. A sensing resolution down to roughly \SI{1}{\milli\bar} pressure was observed with uniaxial force application, and more than two orders of magnitude resistance variation was determined for isostatic pressure below atmospheric pressure.