题　目：Growth Mechanism and CVD Growth Control of Single-Walled Carbon Nanotubes

报告人：professor Shigeo Maruyama

时　间：8月9日（周四）9:50-11:00

地　点：李薰楼468会议室

欢迎参加！

报告摘要：

Growth Mechanism and CVD Growth Control of Single-Walled Carbon Nanotubes 

Shigeo Maruyama

Department of Mechanical Engineering, The University of Tokyo

7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

E-mail: maruyama@photon.t.u-tokyo.ac.jp, URL: http://www.photon.t.u-tokyo.ac.jp/

Recent progress in chemical vapor deposition (CVD) growth of single-walled carbon nanotubes (SWNT) using alcohol as carbon source is discussed. The diameter control, growth alignment control (vertical or horizontal to a substrate) and patterned growth are developed. The diameter was relatively small (around 0.7 nm) within relatively narrow range for our original ACCVD using metal catalysts supported on zeolite particles. However, the diameter is much larger (around 2.1 nm) with wider distribution when we used the vertically aligned condition. The average diameter was reduced to about 1.4 nm by conditioning catalysts recipes with the vertically aligned morphology ^[1]. Finally, vertically aligned small diameter SWNTs such as 0.7 nm was achieved by adding acetonitrile to ethanol ^[2]. At the same time, SWNT was filled with nitrogen gas and the tube wall was also doped with nitrogen. On the other hand, mechanism of horizontally aligned growth of SWNTs on crystal quartz was revealed that the close-packed atomic structure in R-plane was responsible to the alignment ^[3]. Several techniques were developed for the patterned growth of SWNTs by patterning catalyst on a substrate ^[4]. Combining these growth controlled techniques, transparent and flexible field effect transistors (FET) are demonstrated using as-grown SWNTs employed as source, drain and gate electrodes as well as channel ^[5].

Growth mechanism of SWNTs will be briefly discussed based on molecular dynamics (MD) simulations. From our recent MD simulations, carbon structure interacting to a metal cluster during the growth can be classified into two apparently different modes. A preferred structure at lower temperature is "Octopus" mode where several carbon chains are wrapping the metal cluster. Another structure appeared at higher temperature is "VLS" mode where carbon atoms are dissolved in metal cluster. The diameter of nanotube is similar to the metal cluster size for Octopus mode in contract to the VLS mode where the diameter is determined in the nucleated cap structure. The chirality of nanotubes grown in different MD conditions will be discussed.

References

[1] R. Xiang, E. Einarsson, Y. Murakami, J. Shiomi, S. Chiashi, Z.-K. Tang, S. Maruyama, ACS Nano, (2012) in press.

[2] T. Thurakitseree, C. Kramberger, P. Zhao, S. Aikawa, S. Harish, S. Chiashi, E. Einarsson and S. Maruyama, Carbon, 50 (2012) 2635-2640.

[3] S. Chiashi, H. Okabe, T. Inoue, J. Shiomi, T. Sato, S. Kono, M. Terasawa and S. Maruyama, J. Phys. Chem. C, 116 (2012) 6805.

[4] R. Xiang, T. Wu, E. Einarsson, Y. Suzuki, Y. Murakami, J. Shiomi and S. Maruyama, J. Am. Chem. Soc., 131 (2009) 10344.

[5] S. Aikawa, E. Einarsson, T. Thurakitseree, S. Chiashi, E. Nishikawa, S. Maruyama, Appl. Phys. Lett., 100 (2012) 063502.

报告人介绍：

He received Ph.D. in School of Engineering from the University of Tokyo in 1988. He worked as a research associate until 1991, as lecturer for a year, then associate professor from 1993 and as a full professor from 2004 at the University of Tokyo. While he is research associate of the University of Tokyo, he joined Professor Richard Smalley group at Rice University as visiting fellow for about 2 years during 1989 through 1991. During this period, he started to study chemical physics of clusters, fullerenes, and carbon nanotubes. He invented the new CVD technique of SWNTs from alcohol in 2002, so-called ACCVD. He is assigned as program officer of Japan Society for the Promotion of Science (JSPS) and serves as the president of “The Fullerenes, Nanotubes and Graphene Research Society,” since 2011. His about 170 ISI-listed publications have been cited more than 5000 times, resulting the h-index of 39.