Low-Temperature, Dry Transfer-Printing of a Patterned Graphene Monolayer.

Sugkyun Cha,Jin Hyoun Kang,Minjeong Cha,Seojun Lee,Changsoon Kim

doi:10.1038/srep17877

Sugkyun Cha, Jin Hyoun Kang + Show 3 more

Open Access

https://doi.org/10.1038/srep17877

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Abstract

Graphene has recently attracted much interest as a material for flexible, transparent electrodes or active layers in electronic and photonic devices. However, realization of such graphene-based devices is limited due to difficulties in obtaining patterned graphene monolayers on top of materials that are degraded when exposed to a high-temperature or wet process. We demonstrate a low-temperature, dry process capable of transfer-printing a patterned graphene monolayer grown on Cu foil onto a target substrate using an elastomeric stamp. A challenge in realizing this is to obtain a high-quality graphene layer on a hydrophobic stamp made of poly(dimethylsiloxane), which is overcome by introducing two crucial modifications to the conventional wet-transfer method – the use of a support layer composed of Au and the decrease in surface tension of the liquid bath. Using this technique, patterns of a graphene monolayer were transfer-printed on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and MoO3, both of which are easily degraded when exposed to an aqueous or aggressive patterning process. We discuss the range of application of this technique, which is currently limited by oligomer contaminants, and possible means to expand it by eliminating the contamination problem.

Highlights

Graphene, a one-atom-thick layer of carbon atoms arranged in a hexagonal lattice, has outstanding electrical[1,2] and mechanical[3,4] properties, as well as high optical transmittance[5]
When the PDMS stamp was observed by an optical microscope after Step (f) in Fig. 1, it was found that similar defects, albeit smaller in size, were present (Supplementary Fig. S3), indicating that the defects are formed while transferring the graphene layer onto the PDMS surface and are exacerbated during the transfer-printing onto the substrate
We have developed a low temperature, dry process capable of transfer-printing a patterned graphene monolayer grown on Cu foil on a target substrate

Summary

Introduction

A one-atom-thick layer of carbon atoms arranged in a hexagonal lattice, has outstanding electrical[1,2] and mechanical[3,4] properties, as well as high optical transmittance[5]. Electronic devices: for example, it cannot be applied to fabrication of an LED with a top graphene electrode, since the adhesion layer in this case would be placed in the device interior, just beneath the graphene electrode, impeding efficient charge injection Another approach is to transfer-print a graphene layer coated with a ‘self-release’ layer from an elastomeric stamp onto a target substrate[25], where reliable transfer is achieved by choosing an appropriate self-release layer that assures the selective delamination at the interface between that and the elastomer. Jung et al demonstrated a technique capable of transferring graphene monolayers without an adhesion or a self-release layer[26] In this mechano-electro-thermal process, complete transfer, instead, requires application of high temperature (≥ 160 °C) and voltage (≥ 600 V) while a graphene layer grown on Cu foil is pressed onto a target substrate. The first part of this process (a to f), seemingly similar to the conventional wet-transfer technique[18], has two distinct features, which are crucial to obtain a high-quality graphene monolayer on a target substrate

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Conclusion