Frequency Stability of MoS₂ drum resonators at Room Temperature

Nanomechanical resonators hold great promise for ultrasensitive mass and force sensing. The discovery of two-dimensional (2D) materials having ultralow mass and exceptional mechanical properties have made them an ideal choice for NEMS. 2D resonators tend to be a great platform for sensing applications since the minimum detectable mass is proportional to mass of the resonator itself. The limit of detection is also, directly dependent on the measurement uncertainty of resonant frequency (δf/f). Thus, frequency stability is an important performance metric for such resonators. We report frequency stability at room temperature on MoS₂ drum resonators. The Allan deviation (AD) was observed to be of the order of 10^-5 at 150ms integration time for 24V VgDC and AC drive of 70mV. This corresponds to a mass sensitivity of few attograms. We observe that increasing VgAC leads to more improvement in AD as compared to that of VgDC drive. This is due to an enhanced signal to noise ratio. We estimate various types of noise associated with MoS₂ resonator. This work holds promise for ultrasensitive sensing and realizing ultrastable oscillators from 2D materials.