Thermoelectric enhancement in BaGa 2Sb2 by Zn doping

Umut Aydemir*, Alex Zevalkink, Alim Ormeci, Zachary M. Gibbs, Sabah Bux, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

The Zintl phase BaGa2Sb2 has a unique crystal structure in which large tunnels formed by ethane-like dimeric [Sb3Ga-GaSb3] units are filled with Ba atoms. BaGa2Sb2 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 BaGa2Sb2 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 BaGa2Sb2 has a low carrier concentration (∼2 × 1018 h+/cm3) 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) × 1019 h+/cm3. 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 BaGa2Sb2 can thus be considered as a promising new thermoelectric material for intermediate-temperature applications.

Original languageEnglish (US)
Pages (from-to)1622-1630
Number of pages9
JournalChemistry of Materials
Volume27
Issue number5
DOIs
StatePublished - Mar 10 2015

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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