The control of graphene double-layer formation in copper-catalyzed chemical vapor deposition

TL;DR

This paper investigates the mechanisms of multilayer graphene formation during copper-catalyzed chemical vapor deposition, revealing how layer growth depends on proximity to the substrate and how upper layers can be selectively removed.

Contribution

It provides new insights into controlling multilayer graphene growth by understanding layer formation dynamics and using hydrogen etching to modify the process.

Findings

Growth begins with multilayer clusters

Layer growth rate depends on proximity to copper surface

Upper layers can be selectively removed by hydrogen etching

Abstract

The growth of graphene during Cu-catalyzed chemical vapor deposition was studied using 12CH4 and 13CH4 precursor gasses. We suggest that the growth begins by the formation of a multilayer cluster. This seed increases its size but the growth speed of a particular layer depends on its proximity to the copper surface. The layer closest to the substrate grows fastest and thus further limits the growth rate of the upper layers. Nevertheless, the growth of the upper layers continues until the copper surface is completely blocked. It is shown that the upper layers can be removed by modification of the conditions of the growth by hydrogen etching.