Oxidation-assisted graphene heteroepitaxy on copper foil.

Nicolas Reckinger,Jean-François Colomer,Luc Henrard,Frédéric Joucken,Xiaohui Tang,Luc Lajaunie,Raul Arenal,Benoît Hackens,Emmanuel Dubois

doi:10.1039/c6nr02936a

Abstract

We propose an innovative, easy-to-implement approach to synthesize aligned large-area single-crystalline graphene flakes by chemical vapor deposition on copper foil. This method doubly takes advantage of residual oxygen present in the gas phase. First, by slightly oxidizing the copper surface, we induce grain boundary pinning in copper and, in consequence, the freezing of the thermal recrystallization process. Subsequent reduction of copper under hydrogen suddenly unlocks the delayed reconstruction, favoring the growth of centimeter-sized copper (111) grains through the mechanism of abnormal grain growth. Second, the oxidation of the copper surface also drastically reduces the nucleation density of graphene. This oxidation/reduction sequence leads to the synthesis of aligned millimeter-sized monolayer graphene domains in epitaxial registry with copper (111). The as-grown graphene flakes are demonstrated to be both single-crystalline and of high quality.

Highlights

Chemical vapor deposition (CVD) holds great promises for large-scale production of high-quality graphene
Low-pressure CVD leads to the self-limited growth of a graphene monolayer[2] while the same outcome can be obtained by atmospheric pressure CVD (APCVD) provided that the amount of injected hydrocarbon is carefully controlled.[3]
The temperature-time diagram shown in Figure 1a summarizes the so-called “standard” and novel graphene growth conditions, with the corresponding argon and hydrogen flows

Summary

Introduction

Chemical vapor deposition (CVD) holds great promises for large-scale production of high-quality graphene. A few publications (see Table S1 for more details) report on the formation of large Cu(111) grains spanning several millimeters starting from polycrystalline foils,[9,15,16,18] after annealing at temperatures close to the melting point of Cu (1088 °C), where the grain boundary mobility is high After such thermal treatments, Cu naturally adopts the (111) crystallographic orientation since it is thermodynamically the most stable for face-centered cubic metals.[19,20] By contrast, Robinson et al.[20] report the formation of large Cu grains with a dominant (001) texture, the initial main orientation of the Cu foil. Additional details regarding the experimental techniques (scanning electron microscopy, energy-dispersive X-ray spectrometry, electron-backscattering diffraction, low-energy electron diffraction, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, transmission electron microscopy) can be found in the supplementary information (SI)

Results and discussion

Conclusions

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