2003 Fiscal Year Final Research Report Summary
Study on Non-equilibrium Stable Shape and Faceting Process of Nanostructures
| Project/Area Number |
14550031
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
表面界面物性
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| Research Institution | Osaka Electro-Communication University |
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Principal Investigator |
YASUE Tsuneo Osaka Electro-Communication University, Faculty of Engineering, Professor, 工学部, 教授 (00212275)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Nanostructure / Facet structure / Crystal growth / Surface and interface / Nano-material |
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| Research Abstract |
In the present study, we have carried out the analysis of the non-equilibrium stable shape and the facet structure of nanostructures formed by the surface modification using surfactant. The nanostructure formation using anisotropy of the substrate has been also examined, and their facet structure was determined. Through the present study, we discussed on the relationship between the non-equilibrium stable structure and the facet structure of nanostructures. The main results obtained are following ;
(1)Cu nanostructures on hydrogen-terminated Si(111) surface
On the silicon surfaces, there are a lot of dangling bonds, which are chemically quite active. In the present work, such dangling bonds are eliminated by atomic hydrogen to reduce the chemical reactivity, and as the results nanostructures formed on it. At low substrate temperature, nanostructures are a b-phase Cu silicide, and the triangular shape is stable. These nanostructures have facets. From the measurements of the inclination an
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gle for lots of nanostructures by scanning tunneling microscope, the {554}, {110}, {112}, and {114} or {115} facets are assigned. On the other hand at high substrate temperatures, the number of triangular shaped nanostructures deceased and the hexagonal shaped ones appears. This change of the stable shape is caused by the change of the phase of Cu-Si alloy. It is concluded that the non-equilibrium stable shape of nanostructures are mainly determined by the composition or phase of alloy.
(2)Ge nanostructures on anisotropic Si(113) surface
The growth process of Ge on Si( 113) surface has been investigated by using low energy electron microscopy, which enables to observe the dynamic behavior of the crystal growth process. On such anisotropic substrate, nanostructures form by anisotropic strain field on the substrate. Ge nano-cluster and following 3D-island formation was observed at a limited temperature range. In higher temperature region, only 3D-islands form. This behavior is understood by the surface diffusion length. Only when the surface diffusion length is the same order with the terrace width, nano-cluster formation takes place. The facet structure analysis of the 3D-islands was also carried out from the analysis of low energy electron diffraction patterns. Facets on the 3D-islands are assigned as {15x}, where x is integer. Less
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