Fabrication and electrical integration of robust carbon nanotube micropillars by self-directed elastocapillary densification
Fabrication and electrical integration of robust carbon nanotube micropillars by self-directed elastocapillary densification
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DOI：
10.1088/0960-1317/21/4/045033
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发表时间：
2011-04-01
影响因子：
2.3
通讯作者：
Hart, A. John
中科院分区：
文献类型：
--
作者：
De Volder, Michael F. L.;Park, Sei Jin;Hart, A. John
使用图案化催化剂膜通过化学气相沉积 (CVD) 制造的垂直排列碳纳米管 (CNT)“森林”微结构通常具有较低的单位面积 CNT 密度。因此，碳纳米管森林的整体性能较差，而且太脆弱，无法与微加工工艺集成。我们引入了一种新的自引导毛细管致密化方法，其中液体可控地凝结到碳纳米管森林上并从碳纳米管森林中蒸发。与之前将带有碳纳米管的基材浸入液体中的方法相比，我们的冷凝方法提供了明显更均匀的结构，并且能够精确控制碳纳米管堆积密度。我们提出了一套通过自导向毛细作用致密化 CNT 微柱的设计规则和参数研究，并表明自导向毛细管致密化将 CNT 微柱的杨氏模量和电导率提高了三个数量级以上。由于碳纳米管的出色性能，这种可扩展的工艺将有助于将碳纳米管作为功能材料集成到机械、电气、热学和生物医学应用的微加工设备中。
Vertically aligned carbon nanotube (CNT) 'forest' microstructures fabricated by chemical vapor deposition (CVD) using patterned catalyst films typically have a low CNT density per unit area. As a result, CNT forests have poor bulk properties and are too fragile for integration with microfabrication processing. We introduce a new self-directed capillary densification method where a liquid is controllably condensed onto and evaporated from the CNT forests. Compared to prior approaches, where the substrate with CNTs is immersed in a liquid, our condensation approach gives significantly more uniform structures and enables precise control of the CNT packing density. We present a set of design rules and parametric studies of CNT micropillar densification by self-directed capillary action, and show that self-directed capillary densification enhances Young's modulus and electrical conductivity of CNT micropillars by more than three orders of magnitude. Owing to the outstanding properties of CNTs, this scalable process will be useful for the integration of CNTs as a functional material in microfabricated devices for mechanical, electrical, thermal and biomedical applications.