Nickel assisted healing of defective graphene

TL;DR

This study demonstrates that nickel atoms facilitate the healing of defects in graphene sheets through a thermally activated process, leading to perfect graphene reconstruction.

Contribution

It reveals the crucial role of nickel in defect healing of graphene, showing how Ni atoms enable defect repair via bond breaking and reforming.

Findings

Nickel presence results in perfect graphene layers after annealing.

Defect healing is thermally activated at 1000-2500 K.

Ni atoms assist in defect reconstruction through chemical bonds.

Abstract

The healing of graphene grown from a metallic substrate is investigated using tight-binding Monte Carlo simulations. At temperatures (ranging from 1000 to 2500 K), an isolated graphene sheet can anneal a large number of defects suggesting that their healing are thermally activated. We show that in presence of a nickel substrate we obtain a perfect graphene layer. The nickel-carbon chemical bonds keep breaking and reforming around defected carbon zones, providing a direct interaction, necessary for the healing. Thus, the action of Ni atoms is found to play a key role in the reconstruction of the graphene sheet by annealing defects.