Strain-enhanced dynamic ranges in two-dimensional MoS2 and MoTe2 nanomechanical resonators

Abstract

Two-dimensional (2D) materials are promising for atomic-scale, ultralow-power, and highly tunable resonant nanoelectromechanical systems (NEMS) in sensing, communications, and computing. Toward these applications, a broad and controllable linear dynamic range (DR) is desirable for increasing the signal-to-noise ratio (SNR) and reliability. Here, we develop a comprehensive strain-enhanced DR model for 2D NEMS resonators, which is experimentally verified through the tuning of DRs in 2D molybdenum disulfide (MoS2) and molybdenum ditelluride (MoTe2) NEMS resonators using gate-induced strain. We find that the resonance frequency, quality factor, and nonlinear coefficient are all tuned by the gate voltage, which enhance the DR together. Through the guidance of the DR tuning model, we demonstrate DR enhancement by up to 26.9 dB (from 69.5 to 96.4 dB) in a 2D MoS2 NEMS resonator by properly tuning the gate voltage, leading to a theoretical mass resolution of 26 yg (1 yg = 10−24 g). To accurately extract the DR, we further differentiate the quality factors for thermomechanical resonances and for resonances at the largest linear amplitude. This gate-enhanced DR model is also verified using a MoTe2 resonator, with DR enhancement of 7 dB (91.2 to 98.2 dB). The results provide a promising pathway for accurately predicting and optimizing the DRs in NEMS resonators, toward enhanced sensitivity and SNR in mass sensing, radio frequency signal processing, memory, and computing applications.