Nonlinear Damping And Quality Factor In 2d Molybdenum Disulfide Nems Resonators At Varying Electrical Drive

We present a comprehensive technique for accurately extracting the quality (Q) factor when nonlinear damping is taken into account, using two-dimensional (2D) molybdenum disulfide (MoS
2
) nanoelectromechanical systems (NEMS). We experimentally demonstrate linear to Duffing nonlinear resonances by gradually increasing the radio-frequency (RF) driving voltage (v
RF
), with either softening or hardening behavior observed in these 2D NEMS resonators. Through a theoretical model, we find that when nonlinear damping dominates, the nonlinear damping coefficient η can be accurately extracted through iteratively fitting to the Duffing nonlinear resonances and then fitting to the relationship between the full width at half maximum (Δf) vs. frequency at the peak amplitude (f
peak
), for nonlinear resonances with either hardening or softening. By extracting the dissipation parameters, we model the v
RF
tuning of Q factor, which is consistent with experimental data showing ΔQ/Q= 347%. The results provide important insights into the nonlinear damping in 2D NEMS resonators, and provide a technique for modeling the Q factor dependence on electrical driving voltages.