Monolayer Oxidized-MXene Piezo-Resonators with Single Resonant Peak by Interior Schottky Effect

Nanoelectromechanical systems (NEMS) of 2D nanomaterials are potent exploration devices for high-sensitive mechanical coupling, mass testing, and biosensing. Nevertheless, the internal interference from the multiple resonant states easily causes the deviation and overlap of the target signal. Here, an oxidized-MXene resonant system performs the unique response peak at the fundamental frequency f_0,1 of 3.37 ± 0.04 MHz within the ultrawide frequency up to 400 MHz, due to the ferroelectric-conductive structure. This unique resonant peak can effectively avoid the dispute of indistinguishable vibratal states. The resonator exhibits advanced performances with a large dynamic range of 70.41 ± 0.15 dB and low thermomechanical motion spectral density of $669\frac{\text{fm}}{\sqrt{\text{Hz}}}$. The molecular sensing mechanisms of the oxidized-MXene system are systematically studied to achieve repeatable detection with high mass resolution (low to 8.00 ± 0.01 × 10^-19 g). These consequences can afford potential guidelines for the NEMS devices in terms of the credible and legible sensors for ultra-accurate and interference-free measurements.