산화물 환원공정에 의해 제작된 n-형 Bi2Te2.7Se0.3 화합물의 열전특성연구 (Thermoelectric Transport Properties of N-type Bi2Te2.7Se0.3 Compound Prepared by Oxide-Reduction Process)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 58권 / 5호 / 334 ~ 339페이지
· 저자명 : 임영수, 박배건, 이길근

초록

We report the thermoelectric transport properties of n-type Bi2Te2.7Se0.3 compounds prepared by oxide-reduction process. The oxide-reduction process is a recently developed method that can synthesize Bi2Te3-based compounds using only oxide starting materials, which is advantageous in terms of the diversity of the starting materials and cost efficiency. In this study, starting materials of Bi2O3,TeO2 and SeO2 were ball-milled for homogenous mixing, and then oxidized to prepare mixed oxide powders. The mixed oxide powders were reduced at different reduction temperatures (573, 603, 633 and 663 K) for 7 h under hydrogen atmosphere. A single phase of Bi2Te2.7Se0.3 could be achieved when the reduction temperature was higher than 603 K, and the shape of the particles changed from granules to flakes with increasing reduction temperature.
Furthermore, the formation of antisite defects of BiSe was promoted by increasing reduction temperature, which strongly affected the electrical and thermal transport properties of the Bi2Te2.7Se0.3 compounds, which were prepared by spark plasma sintering of the reduced powders. The anisotropic microstructures in the sintered bodies were significantly influenced by the shape of the reduced powders, which was also controlled by the reduction temperature. The thermoelectric transport properties were characterized at room temperature, and the detailed effects of the reduction temperature on these properties are discussed in terms of the anisotropic microstructure and antisite defects.

영어초록

We report the thermoelectric transport properties of n-type Bi2Te2.7Se0.3 compounds prepared by oxide-reduction process. The oxide-reduction process is a recently developed method that can synthesize Bi2Te3-based compounds using only oxide starting materials, which is advantageous in terms of the diversity of the starting materials and cost efficiency. In this study, starting materials of Bi2O3,TeO2 and SeO2 were ball-milled for homogenous mixing, and then oxidized to prepare mixed oxide powders. The mixed oxide powders were reduced at different reduction temperatures (573, 603, 633 and 663 K) for 7 h under hydrogen atmosphere. A single phase of Bi2Te2.7Se0.3 could be achieved when the reduction temperature was higher than 603 K, and the shape of the particles changed from granules to flakes with increasing reduction temperature.
Furthermore, the formation of antisite defects of BiSe was promoted by increasing reduction temperature, which strongly affected the electrical and thermal transport properties of the Bi2Te2.7Se0.3 compounds, which were prepared by spark plasma sintering of the reduced powders. The anisotropic microstructures in the sintered bodies were significantly influenced by the shape of the reduced powders, which was also controlled by the reduction temperature. The thermoelectric transport properties were characterized at room temperature, and the detailed effects of the reduction temperature on these properties are discussed in terms of the anisotropic microstructure and antisite defects.

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