2002 Fiscal Year Final Research Report Summary
Study on intrinsic properties of organic semiconductors appeared under ultrahigh vacuum
| Project/Area Number |
12440197
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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 |
機能・物性・材料
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
TADA Hirokazu Okazaki National Research Institutes, Institute for Molecular Science, Associate Professor, 分子科学研究所, 助教授 (40216974)
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| Co-Investigator(Kenkyū-buntansha) |
TSUKUDA Tatsuuya Okazaki National Research Institutes, Associate Professor, 分子科学研究所, 助教授 (90262104)
ISHIDA Kenji School of Engineering, Kyoto University, Lecturer, 分子科学研究所, 助教授 (20303860)
MATSUSHIGE Kazumi School of Engineering, Kyoto University, Professor, 工学研究科, 教授 (80091362)
TANAKA Shoji Okazaki National Research Institutes, Research Assistant, 分子科学研究所, 助手 (20192635)
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| Project Period (FY) |
2000 – 2002
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| Keywords | organic semiconductor / organic transistor / carrier mobility / ultrahigh vacuum / lattice scattering / carrier injection / hopping transport / tunnel current |
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| Research Abstract |
The mechanism of carrier transport in organic semiconductors and carrier injection from metal electrodes becomes the most important subject to be elucidated for the construction of high performance organic thin film devices. The electrical properties are modified easily by adsorbed gas molecules, which makes it difficult to obtain reliable experimental results. We have studied intrinsic properties under ultrahigh vacuum conditions to strip away the veil of oxygen. We investigated electrical properties of titanyl-phthalocy anine (TiOPc) films under ultrahigh vacuum (UHV) conditions to avoid the influence of gas adsorption. The field-effect measurement revealed that TiOPc films exhibited an n-type semiconducting behavior in UHV. The electron mobility at room temperature was 9 × 10^<-6> cm^2V^<-1>S^<-1> with activation energy of 0.20 eV. The conductivity and carrier density were 9 x 10^<-8> Scm^<-1> and 6 x 10^<16> cm^<-3>, respectively. A clear conversion from n-type to p-type behavior was observed when the films was exposed to oxygen. Strict control of a tmosphere made it possible to obtain a quasi-intrinsic state where both p- and n-type conductions appeared simultaneously.
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