Large and Flat Graphene Flakes Produced by Epoxy Bonding and Reverse Exfoliation of Highly Oriented Pyrolitic Graphite

TL;DR

This paper introduces a novel fabrication method for producing large, flat, and few-layer graphene flakes from highly oriented pyrolytic graphite, suitable for various substrates including flexible ones.

Contribution

The paper presents a new exfoliation technique that yields large, flat, and high-quality graphene flakes with minimal folds, advancing graphene production methods.

Findings

Produced graphene flakes with tens of microns in lateral size

Achieved few-layer and single-layer graphene sheets

Validated flatness and quality using multiple microscopy techniques

Abstract

We present a fabrication method producing large and flat graphene flakes that have a few layers down to a single layer based on substrate bonding of a thick sample of highly oriented pyrolytic graphite (HOPG), followed by its controlled exfoliation down to the few to single graphene atomic layers. As the graphite underlayer is intimately bonded to the substrate during the exfoliation process, the obtained graphene flakes are remarkably large and flat and present very few folds and pleats. The high occurrence of single layered graphene sheets having tens of micron wide in lateral dimensions is assessed by complementary probes including spatially resolved Micro-Raman Spectroscopy, Atomic Force Microscopy and Electrostatic Force Microscopy. This versatile method opens the way of deposition of graphene on any substrates including flexible ones.