2007 Fiscal Year Final Research Report Summary
Study of precise on structural control of carbon nanotubes
| Project/Area Number |
18310086
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nanomaterials/Nanobioscience
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| Research Institution | NTT Basic Research Laboratories |
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Principal Investigator |
KOBAYASHI Yoshihiro NTT Basic Research Laboratories, NTT Basic Research Laboratories, Senior Research Scientist, Group Leader (30393739)
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| Co-Investigator(Kenkyū-buntansha) |
HOMMA Yoshikazu Tokyo University of Science, 理学部, Professor (30385512)
YOSHIMURA Hideyuki Meiji University, 理工学部, Professor (70281441)
MAEDA Fumihiko NTT Basic Research Laboratories, 機能物質科学研究部, Senior Research Scientist, Supervisor (70393741)
SUZUKI Satoru NTT Basic Research Laboratories, 機能物質科学研究部, Senior Research Scientist (00393744)
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| Project Period (FY) |
2006 – 2007
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| Keywords | carbon nanotube / nanomaterial / catalyst / ferittin / chemical vapor deposition / Raman spectrscopy / in situ observation / structure control |
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| Research Abstract |
For the CVD growth of single-walled carbon nanotubes(SWCNTs) on crystalline substrates, the mechanism of self-directional growth on sapphire substrates was explored by using ferritins as growth catalysts. Our analysis of growth behavior on the specially designed substrates indicates that the directional growth is caused by the tip-growth mechanism. This conclusion was confirmed by in-situ SEM observation of the SWCNT growth on sapphire substrates. Chirality-resolved growth kinetics of SWCNTs was investigated by in situ observation of the CVD growth process using Raman spectroscopy. The Raman signals of radial breathing modes from growing SWCNTs were clearly detected for the first time. Our detailed analysis of the growth kinetics clarified the correlation among SWCNT chirality, catalyst diameter and growth duration.
SWCNTs were grown under very clean conditions in a UHV-compatible gas-source MBE system using alcohol as carbon feedstock. The chemical states of grown SWCNTs were character
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ized by in-situ X-ray photoelectron spectroscopy. From the analysis of the spectra, we found that Co catalyst particles maintain "metallic states" even after CVD growth, contrary to the ordinary VLS growth mechanism, and that Fe catalysts partially form oxides after CVD growth at higher temperature, which explains the very low yield of SWCNTs for Fe catalyst compared with Co catalyst.
Very fine metal nanoparticles(diameter of less than 2 nm) were prepared by evaporation of particles(diameter of 3-5 nm, just after calcination) derived from ferritin. The possibility of SWCNT diameter control is suggested by the correlation between diameters of SWCNTs and the catalyst particles. SWCNTs were synthesized from novel catalyst materials, which have been considered to have no catalytic activity, such as semiconductor nanoparticles of Si, Ge, SiC, and noble metal nanoparticles of gold, silver, copper. On basis of these phenomena, we proposed a new growth mechanism that will open up the possibility of chirality control. Less
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Research Products
(147 results)
