Origins of enhanced thermoelectric power factor in topologically insulating Bi0.64Sb1.36Te3 thin films
- Univ. of Michigan, Ann Arbor, MI (United States); Wuhan Univ. of Technology, Wuhan (China)
- Univ. of Michigan, Ann Arbor, MI (United States)
- Wuhan Univ. of Technology, Wuhan (China)
In this paper, we report the enhanced thermoelectric power factor in topologically insulating thin films of Bi0.64Sb1.36Te3 with a thickness of 6–200 nm. Measurements of scanning tunneling spectroscopy and electronic transport show that the Fermi level lies close to the valence band edge, and that the topological surface state (TSS) is electron dominated. We find that the Seebeck coefficient of the 6 nm and 15 nm thick films is dominated by the valence band, while the TSS chiefly contributes to the electrical conductivity. In contrast, the electronic transport of the reference 200 nm thick film behaves similar to bulk thermoelectric materials with low carrier concentration, implying the effect of the TSS on the electronic transport is merely prominent in the thin region. The conductivity of the 6 nm and 15 nm thick film is obviously higher than that in the 200 nm thick film owing to the highly mobile TSS conduction channel. As a consequence of the enhanced electrical conductivity and the suppressed bipolar effect in transport properties for the 6 nm thick film, an impressive power factor of about 2.0 mW m–1 K–2 is achieved at room temperature for this film. Further investigations of the electronic transport properties of TSS and interactions between TSS and the bulk band might result in a further improved thermoelectric power factor in topologically insulating Bi0.64Sb1.36Te3 thin films.
- Research Organization:
- Energy Frontier Research Centers (EFRC), Washington, D.C. (United States). Center for Solar and Thermal Energy Conversion (CSTEC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0000957; PI0000012
- OSTI ID:
- 1370100
- Alternate ID(s):
- OSTI ID: 1236107
- Journal Information:
- Applied Physics Letters, Vol. 108, Issue 4; Related Information: CSTEC partners with University of Michigan (lead); Kent State University; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Thermoelectric Properties of Topological Insulators
|
journal | April 2018 |
Similar Records
Thermoelectric properties of topological insulator Bi{sub 2}Te{sub 3}, Sb{sub 2}Te{sub 3}, and Bi{sub 2}Se{sub 3} thin film quantum wells
Highly Efficient Room‐Temperature Spin‐Orbit‐Torque Switching in a Van der Waals Heterostructure of Topological Insulator and Ferromagnet