2001 Fiscal Year Final Research Report Summary
Fabrication of Self-assembled Film of Silicon Atomic Thin Wires and Its Applications for Optical Devices
| Project/Area Number |
12450128
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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 |
Electronic materials/Electric materials
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TAKAHAGI Takayuki Hiroshima University, Graduate School of Advanced Science of Matter, Professor, 大学院・先端物質科学研究科, 教授 (40271069)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAUE Hiroyuki Hiroshima University, Graduate School of Advanced Science of Matter, Assistant, 大学院・先端物質科学研究科, 助手 (50221263)
SHIGUBARA Shoso Hiroshima University, Graduate School of Advanced Science of Matter, Assistant Professor, 大学院・先端物質科学研究科, 助教授 (10231367)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Oligosilane / Self-assembled film / σ hyper-conjugation / Optical and electrical properties / Conformation / Optical device / Thiol |
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| Research Abstract |
The Si atoms in oligosilane molecular chain bond with two another atoms by σ-electrons like an atomic thin wire. The electrons delocalize in the state of σ-hyper-conjugation and differ from the σ-electron in usual organic compounds. Then, the oligosilane is expected to have rare optical and electrical properties. The degree of σ-hyper-conjugation is considered to depend on conformation of the main molecular chain. In this work, the self-assembled film of oligosilane was formed on the surface of the substrate. The optical and other properties of the film were measured and compared with those of solution and thin film made by the spin court method. As a result, the self-assembled film was confirmed to have the absorption peak assigned to σ-σ^* transition about 330-350 nm in UV/visible light spectrum shifting to the longer wave-length side than solution phase and the spin court film. By the quantum chemistry calculation method, we obtained the result that the HOMO-LUMO energy gap of the t
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wisted gauche-conformer has larger than trans-conformer. As the result, oligosilane molecules in the self-assembled film fixed to the surface of the substrate have the straight trans-conformer with extending a -hyper-conjugation, while oligosilane molecules in the solution and the spin court film have the twisted gauche-conformer with limited a -hyper-conjugation. The result suggests that the preparation of self-assembled film is one of effective methods to control of optical and the electrical properties of oligosilane. We obtained significant information for fabricating optical devices like as EL device. The self-assembled film of the alkylthiol molecules was formed further as a basic research for the fabrication of self-assembled film of chain molecules, and the electronic device as its application was researched. We confirmed that the self-assembled film could work as a tunnel barrier film. We observed quantum electric conduction phenomenon at room temperature in the gold nano-particles with self-assembled film on those surfaces. Less
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