Molecular beam-controlled nucleation and growth of vertically aligned single-wall carbon nanotube arrays
Molecular beam-controlled nucleation and growth of vertically aligned single-wall carbon nanotube arrays
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DOI：
10.1021/jp051531i
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发表时间：
2005-09-08
影响因子：
3.3
通讯作者：
Lowndes, DH
中科院分区：
文献类型：
--
作者：
Eres, G;Kinkhabwala, AA;Lowndes, DH
单壁碳纳米管广泛应用的主要障碍是缺乏可重复的纯材料合成方法。我们描述了一种新的单壁碳纳米管的生长方法，该方法使用前体气体的分子束撞击在涂覆有催化剂薄膜的加热基底上。在这种生长环境中，气体和衬底温度被解耦，并且碳纳米管生长通过表面反应发生，而没有来自均匀气相反应的贡献。这种受控的反应环境表明，单壁碳纳米管的生长是一个复杂的多组分反应，其中不仅C，而且H和O发挥关键作用。这些实验将乙炔鉴定为用于碳网络形成的多产直接构建块，其比其他小分子前体更有效一个数量级。分子喷射实验表明，与最佳的催化剂颗粒尺寸的乙炔分子的入射率在形成单壁碳纳米管和密集的垂直排列的阵列，其中它们是占主导地位的组成部分起着关键作用。垂直取向生长的阈值，生长速率，直径，和壁的碳纳米管的数量与乙炔的入射率和衬底温度系统地相关。
The main obstacle to widespread application of single-wall carbon nanotubes is the lack of reproducible synthesis methods of pure material. We describe a new growth method for single-wall carbon nanotubes that uses molecular beams of precursor gases that impinge on a heated substrate coated with a catalyst thin film. In this growth environment the gas and the substrate temperature are decoupled and carbon nanotube growth occurs by surface reactions without contribution from homogeneous gas-phase reactions. This controlled reaction environment revealed that SWCNT growth is a complex multicomponent reaction in which not just C, but also H, and O play a critical role. These experiments identified acetylene as a prolific direct building block for carbon network formation that is an order of magnitude more efficient than other small-molecule precursors. The molecular jet experiments show that with optimal catalyst particle size the incidence rate of acetylene molecules plays a critical role in the formation of single-wall carbon nanotubes and dense vertically aligned arrays in which they are the dominant component. The threshold for vertically aligned growth, the growth rate, the diameter, and the number of walls of the carbon nanotubes are systematically correlated with the acetylene incidence rate and the substrate temperature.