Rough contact is not always bad for interfacial energy coupling

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Traditional understanding suggests rough surfaces weaken interfacial energy coupling.
• Optimizing energy transfer between materials like graphene and silicon is crucial for device performance.

Purpose of the Study:

• To investigate the effect of sub-nanometer surface roughness on silicon on the energy coupling with single-layer graphene (SLG).
• To challenge the conventional view and explore novel methods for enhancing interfacial thermal resistance.

Main Methods:

• Fabrication of periodic grooves with specific dimensions (2 nm width, 2 nm spacing) on a silicon substrate.
• Characterization of interfacial properties and thermal resistance as a function of groove depth (δ).
• Analysis of interfacial C-Si bond dynamics and forces acting on graphene.

Main Results:

• Sub-nanometer roughness on Si surfaces substantially improves energy coupling with SLG.
• Interfacial thermal resistance decreased by over 10% at a groove depth of 0.54 nm.
• Surface roughness tunes C-Si bonding, creating strong repulsive forces in supported regions that enhance local energy coupling.

Conclusions:

• Introducing sub-nanometer roughness on Si surfaces is a viable strategy to enhance energy coupling with SLG.
• This method offers a new paradigm for tuning material-substrate interactions for soft materials like graphene.
• The findings have implications for designing advanced nanoelectronic and thermal management devices.