Low-temperature-grown continuous graphene films from benzene by chemical vapor deposition at ambient pressure

Jisu Jang,Chunhum Cho,Myungwoo Son,Moon-Ho Ham,Sunki Chung,Kihyeun Kim,Byoung Hun Lee

doi:10.1038/srep17955

Jisu Jang, Chunhum Cho + Show 5 more

Open Access

https://doi.org/10.1038/srep17955

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Journal: Scientific Reports	Publication Date: Dec 1, 2015
Citations: 113	License type: CC BY 4.0

Affiliation: Gwangju Institute of Science and Technology

Abstract

There is significant interest in synthesizing large-area graphene films at low temperatures by chemical vapor deposition (CVD) for nanoelectronic and flexible device applications. However, to date, low-temperature CVD methods have suffered from lower surface coverage because micro-sized graphene flakes are produced. Here, we demonstrate a modified CVD technique for the production of large-area, continuous monolayer graphene films from benzene on Cu at 100–300 °C at ambient pressure. In this method, we extended the graphene growth step in the absence of residual oxidizing species by introducing pumping and purging cycles prior to growth. This led to continuous monolayer graphene films with full surface coverage and excellent quality, which were comparable to those achieved with high-temperature CVD; for example, the surface coverage, transmittance, and carrier mobilities of the graphene grown at 300 °C were 100%, 97.6%, and 1,900–2,500 cm2 V−1 s−1, respectively. In addition, the growth temperature was substantially reduced to as low as 100 °C, which is the lowest temperature reported to date for pristine graphene produced by CVD. Our modified CVD method is expected to allow the direct growth of graphene in device manufacturing processes for practical applications while keeping underlying devices intact.

Highlights

There is significant interest in synthesizing large-area graphene films at low temperatures by chemical vapor deposition (CVD) for nanoelectronic and flexible device applications
Because the “vacuum-free” atmospheric pressure CVD (APCVD) reactor is kept in ambient air for most of the growth time and is exposed to trace amounts of oxidizing contaminants, the inevitable presence of residual oxidizing species during the growth process leads to the oxidative etching of graphene, which introduces defects in the graphene[25,26,27,28]
The optical microscopy (OM) and scanning electron microscopy (SEM) images show the same contrast over the entire film area, in contrast to the film grown by APCVD

Summary

Introduction

There is significant interest in synthesizing large-area graphene films at low temperatures by chemical vapor deposition (CVD) for nanoelectronic and flexible device applications. We demonstrate a modified CVD technique for the production of largearea, continuous monolayer graphene films from benzene on Cu at 100–300 °C at ambient pressure In this method, we extended the graphene growth step in the absence of residual oxidizing species by introducing pumping and purging cycles prior to growth. We developed a modified APCVD route to synthesize graphene on Cu foils, which is called the “oxygen-free APCVD” process In this method, we extended the graphene growth step in the absence of residual oxidizing species that may influence the formation of amorphous and oxidized carbon layers. We extended the graphene growth step in the absence of residual oxidizing species that may influence the formation of amorphous and oxidized carbon layers Using this method with benzene as a carbon feedstock, large-area, continuous graphene sheets with excellent quality were synthesized on Cu foils at 300 °C. The growth temperature was substantially reduced to as low as 100 °C, which is the lowest temperature reported to date for pristine graphene produced by CVD

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Conclusion