Thermoelectric Enhancement in BaGa_2Sb_2 by Zn Doping
Abstract
The Zintl phase BaGa_2Sb_2 has a unique crystal structure in which large tunnels formed by ethane-like dimeric [Sb_3Ga−GaSb_3] units are filled with Ba atoms. BaGa_2Sb_2 was obtained in high purity from ball-milling followed by hot pressing. It shows semiconducting behavior, in agreement with the valence precise Zintl counting and band structure calculations, with a band gap ∼0.4 eV. The thermal conductivity of BaGa_2Sb_2 is found to be relatively low (0.95 W/K m at 550 K), which is an inherent property of compounds with complex crystal structures. As BaGa_2Sb_2 has a low carrier concentration (∼2 × 10^18 h^+/cm^3) at room temperature, the charge carrier tuning was performed by substituting trivalent Ga with divalent Zn. Zn-doped samples display heavily doped p-type semiconducting behavior with carrier concentrations in the range (5−8) × 10^19 h^+/cm^3. Correspondingly, the zT values were increased by a factor of 6 by doping compared to the undoped sample, reaching a value of ∼0.6 at 800 K. Zn-doped BaGa_2Sb_2 can thus be considered as a promising new thermoelectric material for intermediate-temperature applications.
Additional Information
© 2015 American Chemical Society. Received: November 21, 2014; Revised: February 9, 2015; Published: February 11, 2015. U.A. acknowledges the financial assistance of The Scientific and Technological Research Council of Turkey. This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration and was supported by the NASA Science Missions Directorate's Radioisotope Power Systems Technology Advancement Program. We would like to acknowledge the Molecular Materials Research Center (MMRC) at Caltech for allowing use of their instruments for the optical measurements obtained in this work. A.O. thanks Ulrike Nitzsche from IFW Dresden, Germany, for technical help in computational work.Attached Files
Supplemental Material - cm5042937_si_001.pdf
Files
| Name | Size | Download all |
|---|---|---|
|
md5:76310a4bdfd79a1544599ed5a9a4b084
|
414.5 kB | Preview Download |
Additional details
- Alternative title
- Thermoelectric Enhancement in BaGa2Sb2 by Zn Doping
- Eprint ID
- 55424
- DOI
- 10.1021/cm5042937
- Resolver ID
- CaltechAUTHORS:20150302-135522102
- Scientific and Technological Research Council of Turkey (TÜBİTAK)
- NASA/JPL/Caltech
- Created
-
2015-03-03Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field