Energy Dissipation in Graphene Mechanical Resonators with and without Free Edges

Area of Science:

• Materials Science
• Nanotechnology
• Mechanical Engineering

Background:

• Graphene-based nanoelectromechanical systems (NEMS) offer promise for sensitive mass and force sensors due to graphene's unique properties.
• Achieving high quality factors (Q) in graphene resonators is crucial for sensor sensitivity, but energy dissipation remains a significant challenge.

Purpose of the Study:

• To investigate energy dissipation mechanisms in doubly-clamped and circular drumhead graphene resonators.
• To understand the temperature (T) dependence of the quality factor (Q) to identify dominant dissipation pathways.
• To correlate resonator design with energy dissipation and Q factor performance.

Main Methods:

• Fabrication and characterization of doubly-clamped trilayer and circular drumhead graphene resonators.
• Measurement of the temperature dependence of the inverse quality factor (Q⁻¹) for different resonator designs.
• Analysis of Q⁻¹-T curves to identify dominant energy dissipation mechanisms.

Main Results:

• Doubly-clamped trilayer resonators exhibited Q⁻¹ ∝ T² above ~100 K and Q⁻¹ ∝ T⁰.³ below ~100 K, attributed to strain and edge vibrations.
• Circular drumhead resonators showed a linear Q⁻¹-T dependence, indicating suppressed energy dissipation.
• Removal of free edges and clamping metals in drumhead resonators significantly reduced energy dissipation.

Conclusions:

• The study elucidates dominant energy dissipation mechanisms in graphene resonators based on their temperature dependence.
• Circular drumhead designs show superior performance by minimizing energy loss compared to doubly-clamped configurations.
• Findings provide critical insights for designing high-Q graphene resonators for advanced NEMS applications.