Large-scale Epitaxial Growth Kinetics of Graphene: A Kinetic Monte Carlo Study

TL;DR

This study introduces a kinetic Monte Carlo model to simulate large-scale graphene growth kinetics during chemical vapor deposition, revealing geometry-dependent growth mechanisms consistent with experimental observations.

Contribution

A minimal kinetic Monte Carlo model is proposed to simulate atomistic growth kinetics of graphene on mismatched substrates at large scales.

Findings

Growth is dominated by $C_{1}$-attachment at concave fronts.

Growth is dominated by $C_{5}$-attachment at convex fronts.

Simulated growth behavior matches recent STM experiments.

Abstract

Epitaxial growth via chemical vapor deposition is considered to be the most promising way towards synthesizing large area graphene with high quality. However, it remains a big theoretical challenge to reveal growth kinetics with atomically energetic and large-scale spatial information included. Here, we propose a minimal kinetic Monte Carlo model to address such an issue on an active catalyst surface with graphene/substrate lattice mismatch, which facilitates us to perform large scale simulations of the growth kinetics over two dimensional surface with growth fronts of complex shapes. A geometry-determined large-scale growth mechanism is revealed, where the rate-dominating event is found to be $C_{1}$-attachment for concave growth front segments and $C_{5}$-attachment for others. This growth mechanism leads to an interesting time-resolved growth behavior which is well consistent with that observed in a recent scanning tunneling microscopy experiment.