Graphene Nucleation on Transition Metal Surface: Structure Transformation and Role of the Metal Step Edge

TL;DR

This study uses density functional theory to analyze graphene nucleation on transition metal surfaces, revealing structure transformations and the importance of step edges in growth, and proposes seeded graphene for high-quality synthesis.

Contribution

It provides a detailed theoretical analysis of graphene nucleation mechanisms on metal surfaces, highlighting the role of step edges and structure transformations.

Findings

Graphene nucleation is more favorable near step edges than on terraces.

A structural transformation from 1D C chains to 2D sp2 networks occurs at N ~ 10-12.

Seeded graphene can enable large-area high-quality graphene synthesis.

Abstract

The nucleation of graphene on a transition metal (TM) surface, either on a terrace or near a step edge, is systematically explored using density functional theory (DFT) calculations and applying the two-dimensional (2D) crystal nucleation theory. Careful optimization of the supported carbon clusters, CN (with size N ranging from 1 to 24), on the Ni(111) surface indicates a ground state structure transformation from a one-dimensional (1D) C chain to a two-dimensional (2D) sp2 C network at N ~ 10-12. Furthermore, the crucial parameters controlling graphene growth on the metal surface, nucleation barrier, nucleus size, and the nucleation rate on a terrace or near a step edge, are calculated. In agreement with numerous experimental observations, our analysis shows that graphene nucleation near a metal step edge is superior to that on a terrace. Based on our analysis, we propose the use of seeded graphene to synthesize high-quality graphene in large area.