Highly sensitive electromechanical piezoresistive pressure sensors based on large-area layered PtSe$_{2}$ films

TL;DR

This paper demonstrates that thin PtSe₂ films can serve as highly sensitive piezoresistive pressure sensors with negative gauge factors, showing potential for integration into CMOS-compatible NEMS devices.

Contribution

It introduces the use of scalable, low-temperature grown PtSe₂ films as highly sensitive piezoresistive sensors with negative gauge factors, advancing 2D material applications in NEMS.

Findings

High negative gauge factors up to -84.8 measured

Sensors outperform previous values by orders of magnitude

DFT calculations explain the origin of negative gauge factors

Abstract

Two-dimensional (2D) layered materials are ideal for micro- and nanoelectromechanical systems (MEMS/NEMS) due to their ultimate thinness. Platinum diselenide (PtSe$_{2}$), an exciting and unexplored 2D transition metal dichalcogenides (TMD) material, is particularly interesting because its scalable and low temperature growth process is compatible with silicon technology. Here, we explore the potential of thin PtSe$_{2}$ films as electromechanical piezoresistive sensors. All experiments have been conducted with semimetallic PtSe$_{2}$ films grown by thermally assisted conversion of Pt at a CMOS-compatible temperature of 400{\deg}C. We report high negative gauge factors of up to -84.8 obtained experimentally from PtSe$_{2}$ strain gauges in a bending cantilever beam setup. Integrated NEMS piezoresistive pressure sensors with freestanding PMMA/PtSe$_{2}$ membranes confirm the negative gauge factor and exhibit very high sensitivity, outperforming previously reported values by orders of magnitude. We employ density functional theory (DFT) calculations to understand the origin of the measured negative gauge factor. Our results suggest PtSe$_{2}$ as a very promising candidate for future NEMS applications, including integration into CMOS production lines.