›› 2014, Vol. 23 ›› Issue (11): 117202-117202.doi: 10.1088/1674-1056/23/11/117202

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Probing the thermoelectric transport properties of n-type Bi2Te3 close to the limit of constitutional undercooling

冯松科, 李双明, 傅恒志   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • 收稿日期:2014-07-10 修回日期:2014-08-07 出版日期:2014-11-15 发布日期:2014-11-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51074127) and the Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University, China (Grant No. SKLSP201010).

Probing the thermoelectric transport properties of n-type Bi2Te3 close to the limit of constitutional undercooling

Feng Song-Ke (冯松科), Li Shuang-Ming (李双明), Fu Heng-Zhi (傅恒志)   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2014-07-10 Revised:2014-08-07 Online:2014-11-15 Published:2014-11-15
  • Contact: Li Shuang-Ming E-mail:lsm@nwpu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51074127) and the Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University, China (Grant No. SKLSP201010).

摘要: 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 uV/K and an electrical conductivity of 5.6×104 S/m are acquired. The optimal power factor is obtained 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.

关键词: thermoelectric property, directional solidification, Bi2Te3, density functional theory

Abstract: 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 uV/K and an electrical conductivity of 5.6×104 S/m are acquired. The optimal power factor is obtained 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.

Key words: thermoelectric property, directional solidification, Bi2Te3, density functional theory

中图分类号:  (Thermoelectric and thermomagnetic effects)

  • 72.15.Jf
81.30.Fb (Solidification) 74.25.F- (Transport properties) 32.10.Dk (Electric and magnetic moments, polarizabilities)