Toward the Synthesis of Wafer-Scale Single-Crystal Graphene on Copper Foils

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• 作者：Zheng Yan ; Jian Lin ; Zhiwei Peng ; Zhengzong Sun ; Yu Zhu ; Lei Li ; Changsheng Xiang ; E. Lo茂c Samuel ; Carter Kittrell ; James M. Tour
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：October 23, 2012
• 年：2012
• 卷：6
• 期：10
• 页码：9110-9117
• 全文大小：449K
• 年卷期：v.6,no.10(October 23, 2012)
• ISSN：1936-086X

文摘

In this research, we constructed a controlled chamber pressure CVD (CP-CVD) system to manipulate graphene鈥檚 domain sizes and shapes. Using this system, we synthesized large (4.5 mm²) single-crystal hexagonal monolayer graphene domains on commercial polycrystalline Cu foils (99.8% purity), indicating its potential feasibility on a large scale at low cost. The as-synthesized graphene had a mobility of positive charge carriers of 11鈥?00 cm² V^鈥? s^鈥? on a SiO₂/Si substrate at room temperature, suggesting its comparable quality to that of exfoliated graphene. The growth mechanism of Cu-based graphene was explored by studying the influence of varied growth parameters on graphene domain sizes. Cu pretreatments, electrochemical polishing, and high-pressure annealing are shown to be critical for suppressing graphene nucleation site density. A pressure of 108 Torr was the optimal chamber pressure for the synthesis of large single-crystal monolayer graphene. The synthesis of one graphene seed was achieved on centimeter-sized Cu foils by optimizing the flow rate ratio of H₂/CH₄. This work should provide clear guidelines for the large-scale synthesis of wafer-scale single-crystal graphene, which is essential for the optimized graphene device fabrication.

Keywords:

graphene; hexagonal; single-crystal; CP-CVD