2001 Fiscal Year Final Research Report Summary
Electronic Properties of Singvle-Crystal Oxide Films Fabricated on Metal Surfaces
| Project/Area Number |
11440090
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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 |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
MURATA Yoshitada The Univ. of Electro-Communications, Dept. of Appl. Phys. & Chem., Professor, 電気通信学部, 教授 (10080467)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Koji The Univ. of Electro-Communications, Dept. of Appl. Phys. & Chem., Associate Professor, 電気通信学部, 助教授 (20183139)
YAMADA Chikashi The Univ. of Electro-Communications, Dept. of Appl. Phys. & Chem., Professor, 電気通信学部, 教授 (70037266)
SHIGENARI Takeshi The Univ. of Electro-Communications, Dept. of Appl. Phys. & Chem., Professor, 電気通信学部, 教授 (90017335)
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| Project Period (FY) |
1999 – 2000
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| Keywords | α-alumina / β-quartz / single-crystal oxide films / single-crystal metals / band gap narrowing / many-body effect / monolayer film of platinum / grazing incidence X-ray diffraction |
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| Research Abstract |
High-quality single-crystal films of α-Al_2O_3 9A thick and SiO_2 30 A thick have been fabricated on metal surfaces of Ru(0001) and Ni(111), respectively. α-Al_2O_3 was fabricated by a phase transition from γ- to α-Al_]2O_3 having a commensurate structure with Ru(0001). Atomic hydrogen during initial growth of an amorphous SiO_2 film and ambient oxygen atmosphere during annealing of this film were essential in forming the single-crystal SiO_2 film on Ni(111). An extraordinary result that the band gap for the oxide layer decreases with decreasing oxide thickness was preliminarily observed using scanning tunneling spectroscopy (STS). This result was confirmed by medium-resolution electron energy loss spectroscopy, in. which the oxide thickness V. dependence of the band gap was measured by α-Al_2O_3 films with various oxide thicknesses below 35 A. For growing ultra-thin films of transition metals on a single-crystal oxide, i.e. a wide band gap crystal, we have, utilized the band gap narrowing and succeeded in making a monoatomic layer (ML) of a Pt film on α-Al_2O_3(9 A)/Ru(0001). We have investigated electronic properties of the oxide layer using C-O vibrational frequencies of CO adsorbed on Pt(1 ML)/α-Al_2O_3(9 A)/Ru(0001) measured by reflection absorption infrared spectroscopy. On the other hand, the crystal structure of SiO_2 film thick 40 A was investigated by grazing incidence X-ray diffraction using syncrotron radiation. A nice single crystal film of β-quartz is fabricated with a thickness of 30 A and a polycrystalline Ni silicide film 10 A thick is formed with a mosaic structure at the interface. These single-crystal oxide films on metal surfaces are new surface materials, which will open a window against other fields of solid state physics and chemistry.
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