On quality factor improvement in a NEMS resonator with nonlinear damping

Nonlinear damping effects have been reported in experiments on nanoelectromechanical (NEMS) resonators and suggested as a pathway to improve the quality (Q) factors of the resonators. In particular, in a nonlinearly damped Duffing NEMS resonator operating in the hardening regime, it has been shown that white noise excitation can shrink the hysteresis region resulting in higher Q factors. In this paper the authors: (1) find that an analytical expression they previously derived using the method of harmonic balance for the frequency-amplitude relationship of a weakly-excited, nonlinearly damped Duffing NEMS resonator is valid for strong excitation, (2) show analytically and verify numerically that for constant values of the nonlinear damping coefficient, higher amplitude of forcing leads to increase in the resonant frequency, (3) find that white-noise induced stochastic parametric excitation can lead to enhanced Q factors and (4) show that decreasing the nonlinear damping coefficient leads to higher Q-factor. The results, in addition to being theoretically significant, are expected to be important in sensing applications using NEMS resonators.