| 摘要 |
PROBLEM TO BE SOLVED: To obtain a β-FeSi2 thermoelectric semiconductor material of high quality by an extremely simple method by directly bringing high purity iron into contact with high purity silicon in such a manner that the ambient atmospheric pressure and te mp. are specified and specifying the concn. of impurities other than Mn, Al, Co, Cr and Ni and the optical direct energy gap therein. SOLUTION: High purity iron having >=99.9% purity is brought into contact with high purity silicon having <=99.99% purity in an inert gas atmosphere under >=10<-1> Pa gas pressure or in a vacuum atmosphere under <=10<-1> Pa ambient pressure or in a reducing atmosphere under <=1 Pa partial pressure of an oxidizing gas, and the contact part is heated at 700 to 900 deg.C for >=1 min. In this way, the silicon atoms infiltrate into the inside of the iron material to cause solid phase silicide reaction, by which the β-FeSi2 material in which the concn. of impurities other than Mn, Al, Co, Cr and Ni is regulated to <=100 ppm and the optical direct energy band gap is regulated to 0.75 to 0.9 eV can efficiently be obtd. |
