| 摘要 |
PROBLEM TO BE SOLVED: To enhance the figure of merit in thermoelectric conversion of various thermoelectric conversion materials by producing a hydride at a grain boundary through reaction of a thermoelectric semiconductor material and hydrogen or producing a texture having a crystal structure different from that of a mother material at the grain boundary after hydrogen is removed. SOLUTION: After a thermoelectric conversion material is heat treated in hydrogen gas flow under various conditions, a decision is made whether dehydrogenation is performed or not, based on the figure of merit obtained for the thermoelectric conversion material. More specifically, a texture having a crystal structure different from that of a mother material is created at the grain boundary after a hydride is produced at the grain boundary or hydrogen is removed therefrom. Consequently, the figure of merit of Bi-Te system increases by 30-40% to reach at about 1.3, the figure of merit of SiGe system can be substantially doubled, and the figure of merit can be enhanced to about 1.2 for P type and to about 1.9 for N type resulting in drastic improvement of thermoelectric conversion characteristics.
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