| Project/Area Number |
02640248
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Tohoku University |
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Principal Investigator |
NISHITANI Ryusuke Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (50167566)
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| Co-Investigator(Kenkyū-buntansha) |
NISHINA Yuichiro Tohoku University, Institute for Materials Research, Professor, 金属材料研究所, 教授 (90005851)
KASUYA Atsuo Tohoku University, Institute for Materials Research, Associate Professor, 金属材料研究所, 助教授 (10005986)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1991: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1990: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Microcluster / STM / Scanning Tunneling Microscopy / Fine particle / Coalescence / Graphite / Electrochemistry / Electroplating / 電析 / 黒鉛 / 真空蒸着 / 薄膜 |
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| Research Abstract |
In order to analyze electronic and atomic structures of a microcluster with a given number of atoms, we have constructed a system for the preparation of mass-selected microclusters, and an scanning tunneling niicroscope for an ultra-high vacuum system(UHV-STM). The cluster-preparation system consists of zi liigii-current ion gun and a high-resolution mass spectrometer. Our STM is based on a model by Deniuth, and is computcr-cojitrolled with a home-i-nade feed back circuit. The control software is written using Turbo C++ V. 1. In addition to tiic construction of these instruments, we have made STM analyses of the microclusters and fine particles in air, which are prepared by three different methods : (1)thermal vaporization, (2)laser vaporization, and(3)electrochemical reaction. The growth process of gold particles on the graphite surface has been analyzed by STM in air. We have observed cap-shaped microclusters of about 2 nm in diameter in an atomic resolution which serve as nuclei for the gold-film formation. The gold fine-particles are formed at the nucleation sites after the formation of the nuclei. The particles aggregate into larger particles and/or islands of gold films through coalescence between smaller particles. The morphology of particles and islands is dependent on the temperature of the substrate, which is related with the degree of coalescence between particles. The particles on the graphite surface prepared by laser vaporization are also analyzed by STM in air. The degree of formation of nuclei by laser vaporization is 10' times as high as that by thermal vaporization. This fact is associated with higher energy of laservaporized ions, which is analyzed by the time- and space-resolved optical-measurements of fluorescence radiated from vaporized particles. The electrodeposition process is studied by electrochemical STM. We have obtained in-situ STM images during growth and coalescence of particles at liquid-graphite interface.
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