2005 Fiscal Year Final Research Report Summary
Infrared optical device application of rare earth doped nano-titanium dioxide thin films
| Project/Area Number |
16560016
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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 |
Applied materials science/Crystal engineering
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| Research Institution | TOYO University |
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Principal Investigator |
KOMURO Shuji TOYO University, Faculty of Engineering, Professor, 工学部, 教授 (90120336)
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| Co-Investigator(Kenkyū-buntansha) |
森川 滝太郎 東洋大学, 工学部, 教授 (80191013)
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| Project Period (FY) |
2004 – 2005
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| Keywords | nano-crystal / titanium dioxide thin films / laser ablation / infrared emission / photocatalystic effect / erbium |
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| Research Abstract |
The selectively phase controlled TiO_2 thin films has been fabricated on Si substrate using a laser ablation technique. The crystalline structure of the TiO_2 thin films can be controlled simply by the oxygen pressure during the ablation process, where no-O_2 introduction condition provides a rutile type TiO_2 (R-TiO_2) phase only whereas high oxygen pressure condition an anatase type TiO_2 (A-TiO_2) phase only. The thermal treatment contributes to the growth of the crystalline TiO_2, without the crystalline phase transition within the annealing temperature from 300℃ to 900℃. Under the over band-gap excitation, the broad photoluminescence (PL) related to the band-gap was observed at around 440 nm for the R-Tio_2 thin films and at around 420 nm for the A-TiO_2 thin films. Intense and broad PL peaking at about 530 nm newly appeared at low temperature in the A-TiO_2 thin films, not in the R-TiO_2 thin films. It has been understood that the broad PL is induced by an optically-assisted reduction effect that is caused by both the H_2O adsorption and the reduction process of TiO_2 to Ti_2O_3 by UV illumination. The broad PL induced by the optically assisted reduction is preferably sensitive to the A-TiO_2 thin films than the R-TiO_2 thin films.
Furthermore, erbium-doped TiO_2 (TiO_2:Er) thin films with the anatase structure have been prepared on Si substrate by laser ablation. Sharp and intense Er-related emission in the visible region as well as in the IR region has been observed under over-bandgap excitation.. In the JR region, Er-related emission consisted of one main peak located at 1.534 μm and many subpeaks located at around 1.534 μm can be observed even at room temperature. The drastic thermal quenching of the Er-related 1.534 μm emission is also considered due to the optically-assisted reduction effect.
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Research Products
(10 results)
