Development of the discrete electric power-generator from exhaust or waste heat sources using ecologically friendly semiconductors

使用生态友好型半导体开发废气或废热源分立式发电机

• 批准号: 13650317
• 负责人: TAKANASHI Yoshifumi
• 金额: $ 0.77万
• 依托单位: Tokyo University of Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650317/
• 关键词: Environmentally-friendly semiconductor; Thermoelectric materials; Silicides; Magnegium silicide; Pure graphite; Alumina crucible

Mg2Si, an ecologically friendly semiconductor, is a promising thermoelectric material at temperatures ranging 'rom 500 to 800 K.Mg2Si crystals were grown by the vertical Bridgman method in various crucibles made of quartz, alumina, SiNx-coated quartz, CVD pyrolytic graphite, CVD SiC-coated graphite in order to minimize the reaction and sticking of molten Mg-Si during growth.Congruent crystallization was derived from a stoichiometric melt of Mg2Si and incongruent crystallization was derived from nonstoichiometric melts having Mg : Si ratios of 85 : 1 5, 70:30, and 60:40.Grown samples were characterizedby x-ray diffraction and electron-probe microanalysis, and their power factors were calculated from the Seebeck coefficients and electrical-conductivities measured from room temperature to 773 K.The grown crystals were single crystal and showed n-type conductivity in undoped condition. A sample derived from a stoichiometric melt had a Seebeck coefficient of -470 mV/K, while the highest power factor, 1.1x10-5 W/cmK2 at 373 K, was obtained for the sample derived from an incongruent melt with an Mg : Siratio of 70:30.The use of the graphite based crucibles such as pyrolytic and SiC coated graphites caused the carbon incorporati in the grown crystals, resulting in an increase in the Seebeck coefficient and the electrical conductivity.

Mg2Si 是一种生态友好型半导体，是一种很有前途的热电材料，温度范围为 500 至 800 K。Mg2Si 晶体是通过垂直布里奇曼法在由石英、氧化铝、SiNx 涂层石英、CVD 热解石墨、CVD 制成的各种坩埚中生长的碳化硅涂层石墨，以最大限度地减少生长过程中熔融镁硅的反应和粘附。同成分结晶源自Mg2Si 的化学计量熔体和不一致结晶源自 Mg:Si 比例为 85:1、5、70:30 和 60:40 的非化学计量熔体。通过 X 射线衍射和电子探针微量分析及其功率因数对生长的样品进行了表征根据塞贝克系数和从室温到 773 K 测量的电导率计算得出。生长的晶体是单晶并在未掺杂条件下表现出n型导电性。源自化学计量熔体的样品的塞贝克系数为 -470 mV/K，而源自具有 Mg 的不一致熔体的样品在 373 K 时获得最高功率因数 1.1x10-5 W/cmK2：Siratio 70:30。使用基于石墨的坩埚，例如热解石墨和碳化硅涂层石墨，导致生长的碳并入晶体，导致塞贝克系数和电导率增加。

项目成果

S.Kishino, T.Iida, T.Kuji, Y.Takanashi: "Crystal growth of orthorhombic BaSi_2 by the vertical Bridgman method"Thin Solid Films. (In press). (2004)

S.Kishino、T.Iida、T.Kuji、Y.Takanashi：“通过垂直布里奇曼法进行斜方 BaSi_2 的晶体生长”固体薄膜。

M.Yoshinaga, T.Iida, M.Noda, T.Endo, Y.Takanashi: "Bulk crystal growth of Mg_2Si by the vertical Bridgman method"Thin Solid Films. (In press). (2004)

M.Yoshinaga、T.Iida、M.Noda、T.Endo、Y.Takanashi：“通过垂直布里奇曼法进行 Mg_2Si 的块状晶体生长”固体薄膜。