| Project/Area Number |
06640441
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
MATSUYAMA Tomochika (1995) Kyoto Univ., Res.Reactor Institute, Professor, 原子炉実験所, 教授 (05527463)
松山 奉史 (1994) 京都大学, 原子炉実験所, 教授 (50027463)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1995: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | Polysilane / P-Doped polysilane / n-Type semiconductor / Low-dimensional silicon semiconductor / Neutron transmutation doping / Impurity analysis / Number-averabe molecular weight / Neutron activation analysis / 低次元半導体 / 低次元系半導体 |
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| Research Abstract |
If silicon skeleton of polysilane is substitutionally doped with phosphorus, polysilanes become low-dimensional silicon semiconductors with P-impurity. At the present stage, such P-doped polysilanes are available only by means of the neutron transmutation of ^<30>Si. Since the concentration of phosphorus is about 0.1ppm for thermal neutron flux up to 10^<18>/cm^2, the preparation of puriferd polysilanes is an important factor to investigate the physical properties of P-doped polysilanes without perturbation by other impurities.
In the present study, we attempted to prepare highly purified polysilanes using the reductive coupling of di-or tri-chlorosilanes with sodium in refluxing toluene. Then a neutron activation method was used in quantitative analysis of impurity traces. It was found that the polysilanes were mainly contaminated by Cl and Na ascribable to the by-product NaCl and the Cl end group in polymers. The content of both impurities in these polymers was distributed in the range of about 10^<-5> to 10^<-1>/monomer unit. Further development of purification procedure is needed for the investigation of the intrinsic properties of P-doped polysilanes. We also studied a scheme to prepare polysilanes doped with phosphorus at much higher level.
Quantitative analysis of end group in polymer is valid for determination of its numberaverage molecular weight. Since the polysilanes synthesized above contain Cl end groups, neutron activation analysis of the Cl end groups was applied to determine their numberaverage molecular weight. It was revealed that their molecular weight in some cases go up to 10^7. This fact implies that di-or tri-chlorosilanes are polymerized into extremely high molecular weight polymers. Therefore, if their molecular weight is regulated and their cast films are easily formed, it is expected that we can obtain various polymers with unique properties depending on molecular weight.
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