2003 Fiscal Year Final Research Report Summary
Exploitation of spontaneous formation of nano-structures through nonlinear chemical dynamics
| Project/Area Number |
14350454
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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 |
工業物理化学
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
NAKATO Yoshihiro NAKATO,Yoshihiro, 大学院・基礎工学研究科, 教授 (70029502)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANISHI Shuji OSAKA UNIVERSITY, Graduate School of Engineering Science, Assistant, 大学院・基礎工学研究科, 助手 (40333447)
IMANISHI Akihito OSAKA UNIVERSITY, Graduate School of Engineering Science, Associate Professor, 大学院・基礎工学研究科, 助教授 (60304036)
MURAKOSHI Kei Hokkaido University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (40241301)
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| Project Period (FY) |
2002 – 2003
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| Keywords | nonlinear dynamics / autocatalytic mechanism / electrochemical oscillation / nano-wire / metal lattice / super lattice / etching or photoetching / self-organization |
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| Research Abstract |
We have studied spontaneous formation of nano-structures through non-equilibrium nonlinear dynamics for the purpose of exploitation and establishment of a new method for nano-structuring, and obtained the following results : (1)Scratching of H-terminated vicinal Si(111) surfaces with Teflon tweezers in 40% NH_4F led to formation of nano-wires, mainly composed of carbon and fluorine. The successive etching of the Si(111) surfaces with the nano-wires in 40% NH_4F produced surprisingly well-ordered step structures on Si(111). (2)Immersion of H-terminated Si(111) surfaces in aqueous hydrogen halide (HX) solutions caused halogenation of the Si(111) surface (i.e. conversion of surface Si-H bonds to Si-X bonds). The reactions depended largely on experimental conditions such as the kind of hydrogen halide, the presence or absence of dissolved oxygen, and reaction time. (3)The immersion of H-terminated Si(111) in 7.1 M HI at 5℃ produced oriented nano-wires at the surface. High-resolution XPS measurements showed that the nano-wires were composed of silicon iodides or related compounds. The orientation of the nano-wires was explained to arise from the fact that the wires formation occurred under a surface-diffusion limited condition. (4)The shape and size of metal nano-particles could be regulated by photo and electric-field assisted chemical processes. (5)Photo-etching of TiO_2 (rutile) in aq. H_2SO_4 produced ordered rectangular nano-holes and grooves in the <001> direction. (6)The appearance mechanisms for a number of electrochemical oscillations and accompanying spatiotemporal patterns were revealed.
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