Toward the Synthesis of Wafer-Scale Single-Crystal Graphene on Copper Foils
Toward the Synthesis of Wafer-Scale Single-Crystal Graphene on Copper Foils
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DOI：
10.1021/nn303352k
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发表时间：
2012-10-01
期刊：
影响因子：
17.1
通讯作者：
Tour, James M.
中科院分区：
文献类型：
--
作者：
Yan, Zheng;Lin, Jian;Tour, James M.
在本研究中，我们建立了一个控制室压力CVD（CP-CVD）系统来控制石墨烯的畴大小和形状。使用该系统，我们在商业多晶Cu箔（99.8%纯度）上合成了大（类似于4.5 mm（2））单晶六方单层石墨烯畴，表明其以低成本大规模的潜在可行性。合成的石墨烯在室温下在SiO2/Si衬底上具有类似于11000 cm（2）V-1 s（-1）的正电荷载流子的迁移率，表明其与剥离的石墨烯相当的质量。通过研究不同生长参数对石墨烯畴尺寸的影响，探讨了铜基石墨烯的生长机制。铜预处理，电化学抛光和高压退火被证明是抑制石墨烯成核位点密度的关键。108托的压力是用于合成大单晶单层石墨烯的最佳腔室压力。通过优化H-2/CH 4的流速比，在厘米大小的Cu箔上实现了一个石墨烯种子的合成。这项工作应该为大规模合成晶圆级单晶石墨烯提供明确的指导方针，这对于优化石墨烯器件制造至关重要。
In this research, we constructed a controlled chamber pressure CVD (CP-CVD) system to manipulate graphene's domain sizes and shapes. Using this system, we synthesized large (similar to 4.5 mm(2)) 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 similar to 11000 cm(2) V-1 s(-1) 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 H-2/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.