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在单层石墨烯原子拼接 quilts 颗粒和颗粒边界.
Pinshane Y Huang1, Carlos S Ruiz-Vargas, Arend M van der Zande
1School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
Nature
|January 7, 2011
概括
大规模的石墨烯生产导致不可避免的谷物界限. 新的显微镜显示,这些边界削弱了机械强度,但对电气性能影响很小,为二维材料控制提供了洞察力.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 纳米技术 纳米技术
背景情况:
- 多晶材料的特性是由粒径和粒径边界结构决定的.
- 这些效应在像石墨烯这样的二维材料中得到了放大,在这种材料中,缺陷会显著破坏晶体结构.
- 通过化学蒸汽沉积进行大规模的石墨烯生产使得多晶性成为一个常见的特征.
研究的目的:
- 为了研究大规模多晶石墨烯颗粒边界的原子结构和性质.
- 为了弥合石墨烯中原子分辨率和宏观粒度之间的长度尺度差距.
- 为了将颗粒边界结构与石墨烯膜的机械和电气性能联系起来.
主要方法:
- 使用了原子分辨率传输电子显微镜 (TEM) 和衍射过成像的组合.
- 确定了在谷物边界的精确位置和原子排列.
- 绘制了数百个颗粒和边界的地图,描述了它们的位置,方向和形状.
- 与扫描探头和运输测量相关联的显微镜数据.
主要成果:
- 确定五边形-七边形原子对作为合石墨烯颗粒的主要结构.
- 揭示了由倾斜边界连接的细粒的复杂和意想不到的小拼图.
- 证明谷物边界显著降低了石墨烯的机械强度.
- 观察到石墨烯的电性质不会被这些粒度边界大幅改变.
结论:
- 先进的TEM技术可以在多个长度尺度上详细描述石墨烯颗粒结构.
- 石墨烯粒边界虽然削弱了机械完整性,但对电导率的影响有限.
- 这些发现为了解和控制石墨烯和其他2D材料的粒度结构提供了基础,用于实际应用.
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