1996 Fiscal Year Final Research Report Summary
Study of visible luminescence features of porous Si
| Project/Area Number |
07650806
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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 |
Structural/Functional materials
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| Research Institution | Tohoku University |
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Principal Investigator |
WADAYAMA Toshimasa Faculty of Engineering, Tohoku University Associate Professor, 工学部, 助教授 (20184004)
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| Co-Investigator(Kenkyū-buntansha) |
HATTA Aritada Faculty of Engineering, Tohoku University Professor, 工学部, 教授 (70005502)
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| Project Period (FY) |
1995 – 1996
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| Keywords | porous Si / electrochemical anodization / visible photoluminescence / Raman spectra / siloxene / quantum confinement / light emitting Si crystalline |
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| Research Abstract |
Canham first reported a room-temperature visible photoluminescence (PL) from the porous silicon (PS) and since then a large number of investigations have been carried out on the mechanisms responsible for the visible PL as well as on its application to optoelectronic devices. The visible PL from PS samples has been explained, to date, on the basis of quantum confinement effects in Si nanostructures formed PS layrs or the formation of wide-gap surface chemical species such as siloxene. Further experimental as well as theoretical work should be needed for more precise discussion of the strong visible PL mechanisms. Most of the PL spectra reported were measured in air after the treatments and dynamic changes in the PL spectra of PS in the process of various treatments are yet to be elucidated. In situ PL analysis of the samples under the various treatments conditions would, thus, provide us an important clue to understand the mechanisms of the visible PL of PS.
In the present study, visibl
… More
e luminescence and Raman spectral changes of porous Si during several treatments were recorded in-situ. An exposure to F_2 under Ar^+ laser light (488 nm) irradiation at 373 K leads to change in photoluminescence (PL) band intensity as well as its peak position. At early stage of the exposure, the PL band at 750 nm peak decreased in intensity and a new band emerged at 600 nm. After 30 min from the beginning of the exposure dominates the spectrum while the band at 750 nm almost disappeared. When the sample after the F_2 treatment was exposed to H_2O vapor, the PL intensity around 750 nm increased. The average particle size of the porous Si during the F_2 exposure evaluated from Raman measurements was remained unchanged during the treatments. Further, PL band intensity change of the sample during electrochemical treatments was recorded. The results showed that the PL intensity depended strongly upon the electrolytes.
These results suggest that surface chemical structure of the sample species strongly influence the observed PL spectral features. Less
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