Monolayer MXene Nanoelectromechanical Piezo-Resonators with 0.2 Zeptogram Mass Resolution

Abstract

2D materials-based nanoelectromechanical resonant systems with high sensitivity can precisely trace quantities of ultra-small mass molecules and therefore are broadly applied in biological analysis, chemical sensing, and physical detection. However, conventional optical and capacitive transconductance schemes struggle to measure high-order mode resonant effectively, which is the scientific key to further achieving higher accuracy and lower noise. In the present study, the different vibrations of monolayer Ti₃ C₂ Tx MXene piezo-resonators are investigated, and achieve a high-order f_2,3 resonant mode with a ≈234.59 ± 0.05 MHz characteristic peak due to the special piezoelectrical structure of the Ti₃ C₂ Tx MXene layer. The effective measurements of signals have a low thermomechanical motion spectral density (9.66 ± 0.01 $\frac{fm}{\sqrt{Hz}}$ ) and an extensive dynamic range (118.49 ± 0.42 dB) with sub-zeptograms resolution (0.22 ± 0.01 zg) at 300 K temperature and 1 atm. Furthermore, the functional groups of the Ti₃ C₂ Tx MXene with unique adsorption properties enable a high working range ratio of ≈3100 and excellent repeatability. This Ti₃ C₂ Tx MXene device demonstrates encouraging performance advancements over other nano-resonators and will lead the related engineering applications including high-sensitivity mass detectors.

Keywords: MXene; functional group; mass sensor; piezoelectric; resonator.