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Nano Research

Article Title

Ultrahigh density modulation of aligned single-walled carbon nanotube arrays

Authors

Bin Wu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Dechao Geng, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Yunlong Guo, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Liping Huang, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Jianyi Chen, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Yunzhou Xue, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Gui Yu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Yunqi Liu, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Hisashi Kajiura, Material Laboratory, Sony Corporation, Atsugi Tec. No.2 4-16-1 Okata Atsugi, Kanagawa 243-0021, Japan
Yongming Li, Material Laboratory, Sony Corporation, Atsugi Tec. No.2 4-16-1 Okata Atsugi, Kanagawa 243-0021, Japan

Keywords

SWNT density, chemical vapor deposition, periodic growth, growth mechanism

Abstract

ABSTRACT Controlling the densities of aligned single-walled carbon nanotube arrays (SWNTs) on ST-cut quartz is a critical step in various applications of these materials. However the growth mechanism for tuning SWNT density using the chemical vapor deposition (CVD) method is still not well understood, preventing the development of efficient ways to obtain the desired results. Here we report a general “periodic” approach that achieves ultrahigh density modulation of SWNT arrays on ST-cut quartz substrates—with densities increased by up to ~60 times compared with conventional methods using the same catalyst densities—by varying the CH4 gas “off” time. This approach is applicable to a wide range of initial catalyst densities, substrates, catalyst types and growth conditions. We propose a general mechanism for the catalyst size-dependent nucleation of SWNTs associated with different free carbon concentrations, which explains all the observations. Moreover, the validity of the model is supported by systematic experiments involving the variation of key parameters in the “periodic” CVD approach.

Graphical Abstract

Publisher

Tsinghua University Press

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