Mechanism of Electrochemical Delamination of Two-Dimensional Materials from Their Native Substrates by Bubbling.

Jie Sun,Chen Xu,Xin Liu,Jun Deng,Lihui Liu,Weiling Guo,Xing Fan

doi:10.3390/s151229888

Abstract

A capacitor-based circuit model is proposed to explain the electrochemical delamination of two-dimensional materials from their native substrates where produced gas bubbles squeeze into the interface. The delamination is actually the electric breakdown of the capacitor formed between the solution and substrate. To facilitate the procedure, the backside of the ubstrate has to be shielded so that the capacitor breakdown voltage can be reached. The screening effect can be induced either by nonreactive ions around the electrode or, more effectively, by an undetachable insulator. This mechanism serves as a guideline for the surface science and applications involving the bubbling delamination.

Highlights

A monolayer of carbon atoms organized in a graphitic lattice, has emerged as a material with high potential in various aspects of futuristic electronics
The roadmap for graphene [1] predicts it to be commercialized as flexible transparent electrodes for optoelectronic devices within a few years, but graphene is just the tip of the iceberg when considering the large family of two-dimensional (2D) materials
MoS2 is a semiconductor that can serve as the transistor channel material in post-silicon electronics

Summary

Introduction

A monolayer of carbon atoms organized in a graphitic lattice, has emerged as a material with high potential in various aspects of futuristic electronics. Graphene is grown by CVD on Cu, which needs to be etched off so that the graphene can be transferred to insulators This poses a threat to the environment due to the heavy metal pollution, and dramatically increases the raw materials cost. A transfer technique based on the mechanical separation of graphene from metal foils by H2 bubble formation at the cathode of a water electrolytic cell was proposed [7,8,9,10,11,12], where the catalyst foils are not consumed and can be recycled for re-growth of 2D materials. We studied experimentally the delamination process of a thin layer of spin-coated polymethyl methacrylate (PMMA) polymer from the surface of platinum foils. It will contribute to the understanding of this interesting surface science subject, and serve as a guideline for real applications derived from the bubbling transfer of 2D materials

Experimental Section

Conclusions