Probing the thermoelectric transport properties of n-type Bi2Te3 close to the limit of constitutional undercooling
Bulk n-type Bi2Te3 single crystals with optimized chemical composition were successfully prepared by a high temperature-gradient directional solidification method. We investigate the influence of alloy microstructure, chemical composition, and growth orientation on the thermoelectric transport prope...
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| Published in | 中国物理B：英文版 no. 11; pp. 476 - 482 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
01.11.2014
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1674-1056 2058-3834 |
| DOI | 10.1088/1674-1056/23/11/117202 |
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| Summary: | Bulk n-type Bi2Te3 single crystals with optimized chemical composition were successfully prepared by a high temperature-gradient directional solidification method. We investigate the influence of alloy microstructure, chemical composition, and growth orientation on the thermoelectric transport properties. The results show that the composition of single-crystal Bi2Te3 alloy, along the c axis direction, could be slightly tuned by changing the growth rate of the crystal. At a rate of 18 mm/h, the formed Bi2Te3 crystal exhibits good thermoelectric properties. At 300 K, a maximum Seebeck coefficient of -245 μV/K and an electrical conductivity of 5.6 × 10 4 S/m are acquired. The optimal power factor is ob- tained as 3.3 × 10 -3 W/K2m, with a figure of merit of 0.74. It can be attributed to the increased tellurium allocation in the Bi2Te3 alloys, as verified well by the density functional theory caLculations. |
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| Bibliography: | Feng Song-Ke, Li Shuang-Ming, and Fu Heng-Zhi（ State Key Laboratory of Solidilication Processing, Northwestern Polytechnical University, Xi＇an 710072, China） Bulk n-type Bi2Te3 single crystals with optimized chemical composition were successfully prepared by a high temperature-gradient directional solidification method. We investigate the influence of alloy microstructure, chemical composition, and growth orientation on the thermoelectric transport properties. The results show that the composition of single-crystal Bi2Te3 alloy, along the c axis direction, could be slightly tuned by changing the growth rate of the crystal. At a rate of 18 mm/h, the formed Bi2Te3 crystal exhibits good thermoelectric properties. At 300 K, a maximum Seebeck coefficient of -245 μV/K and an electrical conductivity of 5.6 × 10 4 S/m are acquired. The optimal power factor is ob- tained as 3.3 × 10 -3 W/K2m, with a figure of merit of 0.74. It can be attributed to the increased tellurium allocation in the Bi2Te3 alloys, as verified well by the density functional theory caLculations. 11-5639/O4 thermoelectric property, directional solidification, Bi2Te3, density functional theory |
| ISSN: | 1674-1056 2058-3834 |
| DOI: | 10.1088/1674-1056/23/11/117202 |