Visualization of Horizontally-Aligned Single-Walled Carbon Nanotube Growth with 13C/12C Isotopes

J. Phys. Chem. C, 112 (6), 1735 -1738, 2008. 10.1021/jp709737q S1932-7447(70)09737-6
Web Release Date: November 28, 2007

Visualization of Horizontally-Aligned Single-Walled Carbon Nanotube Growth with ¹³C/¹²C Isotopes

Hiroki Ago,* Naoki Ishigami, Naoki Yoshihara, Kenta Imamoto, Seiji Akita, Ken-ichi Ikeda, Masaharu Tsuji, Tatsuya Ikuta, and Koji Takahashi

Institute for Materials Chemistry and Engineering, Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, PRESTO, Japan Science and Technology Agency (JST), Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531, and Graduate School of Engineering, Kyushu University, Motooka, Fukuoka 819-0395, Japan

Received: October 5, 2007

In Final Form: October 25, 2007

Abstract:

Horizontally aligned growth of single-walled carbon nanotubes (SWNTs) on single-crystal surfaces has attracted great interest in terms of nanoelectronic applications, but their growth mechanism is not fully understood. We report on the ¹³C/¹²C isotope-labeled growth of SWNTs on a sapphire surface to visualize their growth process. Switching carbon feedstock from ¹³CH₄ to ¹²CH₄ during SWNT growth induces a gradient distribution of the carbon isotopes along the tube axis. From the Raman mapping analysis, we succeeded to observe the gradual change in the isotope distribution of individual SWNTs. The results indicate the base-growth mode for the horizontally aligned SWNTs, which suggests that nanotube-sapphire interaction is essential to alignment. This method offers a unique technique to analyze the nanotube growth mechanism and kinetics.

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