2007 Fiscal Year Final Research Report Summary
Growth of conductive suboxide films and the study of the functionalities of the films
| Project/Area Number |
17550139
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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 |
Functional materials chemistry
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| Research Institution | Rikkyo University |
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Principal Investigator |
EDAMOTO Kazuyuki Rikkyo University, Faculty of Science, Professor (80185123)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Thin film / Suboxide / Single-crystal epitaxy / Angle-resolved photoemission spectroscopy / Resonant photoemission spectroscopy |
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| Research Abstract |
Ti monoxide(TiO) has attracted much attention in recent years because it is predicted to have an interesting combination of useful properties such as extreme hardness, a high melting point and metallic conductivity. However, very limited information has been obtained as to the physical and chemical properties of TiO, because it is difficult to synthesize the single-crystal under an atmospheric condition. The aim of this study is to synthesize the TiO single-crystal film by Ti deposition onto Ag(100) in an O_2 atmosphere.
It was found that the TiO_2 film with a(5×1) periodicity is formed by Ti deposition on Ag(100) in O_2 at 10^<-5>-10^<-7> Torr and subsequent annealing at 600℃. On the other hand, the TiO fihn with a(1×1) periodicity was formed by Ti deposition in 02 at 10^<-8>-3×10^<-9> Ibrr and subsequent annealing at 600℃. Therefore, it is concluded that the TiO_2 and TiO films can be selectively formed on Ag(100) by the control of the O_2 pressure during the deposition.
The electronic structure of the TiO film on Ag(100) was investigated by angle-resolved photoemission spectroscopy. The conduction band and the valence band were found at 0-2 eV and 4-8 eV, respectively. Resonant photoemission measurements showed that the spectral intensity of the conduction band exhibits the resonant behavior characteristic of the Ti 3d photoionization cross section, suggesting that the band is mostly composed of Ti 3d component. The two-dimensional band structure was measured, and it was found that the conduction band includes partially filled metallic states. The overall results are compatible with the results of previous theoretical band-calculations for the TiO crystal.
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