| Project/Area Number |
17360318
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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 |
Inorganic materials/Physical properties
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| Research Institution | University of Tsukuba |
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Principal Investigator |
FUJITA Jun-ichi University of Tsukuba, Graduate School of and Apploed Sciences, Associate Professor (10361320)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,860,000 (Direct Cost: ¥15,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2007: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2006: ¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 2005: ¥7,100,000 (Direct Cost: ¥7,100,000)
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| Keywords | Scanning transmission electron microscope / amorphous carbon / carbon nanotube / solid state reaction / catalyst / graphitization / local electric field / probe / カーボンナノチューブ / 鉄微粒子 / 電子・イオン励起反応 / 走査型透過電子顕微鏡 / in-situモニタリング / 走査型透過顕微鏡 |
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| Research Abstract |
This research had focused on following two categories, one was development of handling and visualization technique for solid state carbon nanotube growth, and the second was analysis of carbon nanotube growth by means of in-situ monitoring under scanning transmission electron microscope image. We had developed an ultra-sharp probe having less than 5 nm at the tip curvature in order to manipulate and control the movement of iron catalyst during solid state nanotube growth. Field emissions from a multi-walled carbon nanotube soften the bottom of the tungsten by Joule heating, and the coulomb attraction to the nanotube finery pulled off from the tungsten tip resulted in an ultra sharp apex of the tungsten probe having 5 nm in of curvature. We also found that a locally enhanced field at the probe apex can be visualized using scanning transmission electron microscopy (STEM) under low accelerating voltage operation. By using these technique, we investigated the movement of iron catalyst that migrated into an amorphous matrix in order to clarify the driving mechanism of the catalyst and its crystal. The diffusion coefficient of the iron catalyst was found to be about 0.016-0.06 m^2/min. and the activation energy was estimated to about 1.8 eV. If we assume the catalyst was cubic iron-carbon compound, crystal orientation that formed <100> catalyst// c-axis graphite was frequently observed. We also found a new graphitization mechanism that was induced at the interface surface of liquid Ga.
Based on those results combining further develop our in-situ monitoring and handling technique, we will accelerate the research toward to realize precision control of diameter and chirality of carbon nanotube, and toward artificial graphene based nano application.
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