Graphene Nanoelectromechanical Systems
- Author(s): Miao, Tengfei
- Advisor(s): Bockrath, Marc
- et al.
Graphene, a carbon-based two-dimensional material, has remarkable electrical and mechanical properties, making it an ideal material for studying the Nanoelectromechanical Systems (NEMS). In this thesis, we focus on the performance of few-layer graphene NEMS resonators in drumhead geometry. We will discuss the experimental techniques and studies on their intrinsic properties, nonlinear dynamics and quality factor. We report our measurement on the coefficient of the Duffing nonlinearity, suggesting a geometric origin of this term. The line width of resonance at large drives is enhanced by nonlinear damping, in qualitative agreement with recent theory of damping by radiation of in-plane phonons. The amplitude of response is parametrically amplified due to periodic thermal expansion from the ac source-drain voltage, resulting an anomalously large line width at the largest drives. We observe Q scales inversely with the temperature. We develop a model that includes the intermodal coupling in tensioned graphene resonators and demonstrate Q is determined by the stochastic frequency broadening rather than frictional damping. We will also report our work on a graphene/h-BN (hexagonal boron nitride) drum resonator and discuss its potential applications.