Atomic structure of interconnected few-layer graphene domains.

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Physics

Background:

• Few-layer graphene (FLG) synthesis via atmospheric pressure chemical vapor deposition (AP-CVD) results in interconnected domains.
• Understanding the atomic structure at the interfaces between these domains is critical for controlling material properties.
• Previous studies have not fully elucidated the distinct mechanisms of FLG domain interconnection.

Purpose of the Study:

• To investigate the atomic structure at the boundary interfaces of interconnected FLG domains.
• To identify and differentiate the primary processes by which FLG domains interconnect.
• To correlate microscopic observations with simulated data for validation.

Main Methods:

• Aberration-corrected high-resolution transmission electron microscopy (HRTEM) was employed to examine atomic structures.
• Analysis of Moiré patterns in HRTEM images to detect rotational stacking faults.
• HRTEM contrast profile analysis and multi-slice transmission electron microscopy (TEM) image simulations were used for differentiation and validation.

Main Results:

• Moiré patterns indicated rotational stacking faults extending up to ~100 nm in boundary regions.
• Two main interconnection processes were identified: overgrowth of graphene sheets and direct atomic bonding.
• Distinct HRTEM contrast profiles differentiated between terminating (edge contrast) and atomically bonded (no contrast) interfaces, even under defocus.

Conclusions:

• The study reveals specific atomic-level details of FLG domain interconnectivity.
• The findings provide a method to distinguish between different types of graphene interconnects based on HRTEM contrast.
• This understanding is vital for optimizing AP-CVD synthesis of high-quality FLG materials.