Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) Surface

TL;DR

This paper proposes a novel two-step method using a superstructured Cu-Mn surface and hydrocarbon seeding to suppress grain boundaries in graphene growth, aiming for large-scale single-crystal graphene fabrication.

Contribution

It introduces a new kinetic pathway and surface engineering approach to effectively prevent grain boundary formation during graphene growth.

Findings

Density functional theory identifies misorientation causes GBs.

Hydrocarbon seeding on Cu-Mn surface suppresses GBs.

Method enhances potential for large-scale single-crystal graphene.

Abstract

As undesirable defects, grain boundaries (GBs) are widespread in epitaxial graphene using existing growth methods on metal substrates. Employing density functional theory calculations, we first identify that the misorientations of carbon islands nucleated on a Cu(111) surface lead to the formation of GBs as the islands coalesce. We then propose a two-step kinetic pathway to effectively suppress the formation of GBs. In the first step, large aromatic hydrocarbon molecules are deposited onto a $\sqrt{3}\times\sqrt{3}$ superstructured Cu-Mn alloyed surface to seed the initial carbon clusters of a single orientation; in the second step, the seeded islands are enlarged through normal chemical vapor deposition of methane to form a complete graphene sheet. The present approach promises to overcome a standing obstacle in large scale single-crystal graphene fabrication.