2000 Fiscal Year Final Research Report Summary
Application of Multilayered Structure to Thermoelectric Materials
| Project/Area Number |
10450262
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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 |
Structural/Functional materials
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
MORII Kenji Osaka Prefecture University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10101198)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUI Toshiyuki Osaka Prefecture University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (20219372)
TSUDA Hiroshi Osaka Prefecture University, Graduate School of Engineering, Lecturer, 大学院・工学研究科, 講師 (80217322)
MABUCHI Hiroshi Osaka Prefecture University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (70109883)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Thermoelectrics / Thin multilayered films / Iron beam sputtering / CoSb_3 / Carbonization of Si / SiC / Impurity doping / Thermo-electric properties |
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| Research Abstract |
The purpose of this work is to understand the controlling factors to increase drastically the dimensionless figure-of-merit of thermoelectrics based on materials technological viewpoints. Nonostructural materials were fabricated by annealing thin multilayered films or by applying chemical vapor transport, and the effects of their microstructural parameters on the thermoelectric properties were examined. We focused on the thermoelectrics such as CoSb_3 and 3C-SiC for high temperature applications.
1. Fabrication and thermoelectric properties of CoSb_3 thin films
Thin films of skutterudite CoSb_3 with nanocrystallites were prepared, and the microstructures as well as thermoelectric properties were evaluated as a function of temperature. It was shown that the electrical resistivity and Seeback coefficient of the materials were depended significantly on the crystallite size, impurity doping and the presence of a second phase. With decreasing crystallites to a nano-size scale, the energy filtering effect of charge carriers is assumed to play an important role for increasing thermoelectric performance of the materials.
2. Fabrication and thermoelectric properties of 3C-SiC nanostructures
3C-SiC was successfully prepared by chemical vapor transport of C as a CO gas to a Si substrate at 1300C.The SiC was composed of nanocrystallites and pores with a size renging 10〜100nm depending on the reaction conditions, and had an apparent relative-density of about 60%. It was observed that most part of impurity elements included naturally in graphite powders or mixed artificially to the powders and also those in the Si substrate were transported to the reacted SiC and could act as dopants. The thermoelectric properties of the 3C-SiC produced by this method could be improved with reducing crystallites, introducing nanopores and controlling carrier densities by impurity doping, and could be expected to apply to high performance thermoelectrics operating high temperatures.
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Research Products
(6 results)
