Linking Crystal Phase to Frequency Scaling Based on Nanomechanical Resonators

Nanoelectromechanical systems (NEMS) based on atomically-thin$\text{MoSe}_{2}$have attracted significant attention owing to their excellent material properties and dynamic frequency behaviors. Beyond the widely studied 2 H phase, the mechanical properties of$3 \mathrm{R}-\text{MoSe}_{2}$remain unexplored. Here, we utilize$\text{MoSe}_{2}$NEMS resonators to elucidate their frequency scaling behavior and determine the mechanical parameter of 3R-MoSe2. We reveal a pronounced phasedependent contrast in Young's modulus:$\sim 71 \text{GPa}$for$\text{3RMoSe}_{2}$and$\sim 127 \text{GPa}$for$2 \mathrm{H}-\text{MoSe}_{2}$. By establishing a “phase - frequency scaling” relationship, we provide the essential materials parameter which are directly relevant to$\text{MoSe}_{2}$-based NEMS resonators and enable phaseengineered frequency control for NEMS components.