Advertisement

Journal of Electronic Materials

, Volume 38, Issue 7, pp 1423–1426 | Cite as

Thermal Stability and Phase Purity in Polycrystalline Ba8Ga x Ge46−x

  • Ali Saramat
  • Eric S. Toberer
  • Andrew F. May
  • G. Jeffery Snyder
Article

Polycrystalline Ba8Ga x Ge46−x exhibits promising thermoelectric performance with the figure of merit ZT close to that of single crystals. Polycrystalline Ba8Ga x Ge46−x is promising for applications, but reproducibility and thermal stability of thermoelectric properties need to be demonstrated. Polycrystalline samples of Ba8+dGa x Ge46−x -type clathrates (15.0 ≤ x ≤ 16.8 with varied nominal Ga content and d = 0 or 0.2) were prepared by direct reaction of the elements, followed by ball milling and hot pressing. Trace Ge impurity was observed (<1.0 wt.%) depending on the synthesis method. The electrical resistivity was stable in measurements up to 1000 K, regardless of Ge impurity. However, measurements to 1050 K resulted in irreversible increase in carrier concentration while the carrier mobility remained unchanged.

Keywords

Clathrate electrical resistivity carrier concentration Ba8Ga16Ge30 thermoelectricity 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Notes

Acknowledgement

The Beckman Institute at Caltech, the Swedish Bengt Lundqvist Minne Foundation, and JPL-NASA are greatly acknowledged for financial support.

References

  1. 1.
    A. Saramat, G. Svensson, A.E.C. Palmqvist, C. Stiewe, E. Mueller, D. Platzek, S.G.K. Williams, D.M. Rowe, J.D. Bryan, G.D. Stucky, J. Appl. Phys. 99, 023708 (2006) doi: 10.1063/1.2163979 CrossRefADSGoogle Scholar
  2. 2.
    E.S. Toberer, M. Christensen, B·B. Iversen, G.J. Snyder. Phys. Rev. B 77, 075203 (2008) doi: 10.1103/PhysRevB.77.075203 CrossRefADSGoogle Scholar
  3. 3.
    Y. Gelbstein, Z. Dashevsky, M.P. Dariel. Physica B 363, 196 (2005) doi: 10.1016/j.physb.2005.03.022 CrossRefADSGoogle Scholar
  4. 4.
    C·B. Vining, W. Laskow, J.O. Hanson, R.R. Vanderbeck, P.D. Gorsuch. J. Appl. Phys. 69, 4333 (1991) doi: 10.1063/1.348408 CrossRefADSGoogle Scholar
  5. 5.
    X. Shi, H. Kong, C·P. Li, C. Uher, J. Yang, J.R. Salvador, H. Wang, L. Chen, W. Zhang. Appl. Phys. Lett. 92, 182101 (2008) doi: 10.1063/1.2920210 CrossRefADSGoogle Scholar
  6. 6.
    V·K. Zaitsev, M.I. Fedorov, E.A. Gurieva, I·S. Eremin, P·P. Konstantinov, A.Y. Samunin, M.V. Vedernikov. Phys. Rev. B 74, 045207 (2006) doi: 10.1103/PhysRevB.74.045207 CrossRefADSGoogle Scholar
  7. 7.
    S.R. Culp, S.J. Poon, N. Hickman, T.M. Tritt, J. Blumm. Appl. Phys. Lett. 88, 042106 (2006) doi: 10.1063/1.2168019 CrossRefADSGoogle Scholar
  8. 8.
    G.J. Snyder, E.S. Toberer. Nat. Mater. 7, 105 (2008) doi: 10.1038/nmat2090 PubMedCrossRefADSGoogle Scholar
  9. 9.
    J.D. Bryan, N·P. Blake, H. Metiu, G.D. Stucky, B·B. Iversen, R.D. Poulsen, A. Bentien. J. Appl. Phys. 92, 7281 (2002) doi: 10.1063/1.1519334 CrossRefADSGoogle Scholar
  10. 10.
    H. Anno, M. Hokazono, M. Kawamura, J. Nagao, and K. Matsubara, Proceedings of the 21st International Conference on Thermoelectrics, 2002, p. 77.Google Scholar
  11. 11.
    J. Martin, S. Erickson, G.S. Nolas, P. Alboni, T.M. Tritt, J. Yang. J. Appl. Phys. 99, 044903 (2006) doi: 10.1063/1.2171775 CrossRefADSGoogle Scholar
  12. 12.
    J. Martin, H. Wang, G.S. Nolas. Appl. Phys. Lett. 92, 222110 (2008) doi: 10.1063/1.2939438 CrossRefADSGoogle Scholar
  13. 13.
    V.L. Kuznetsov, L.A. Kuznetsova, A.E. Kaliazin, D.M. Rowe. J. Appl. Phys. 87, 7871 (2000) doi: 10.1063/1.373469 CrossRefADSGoogle Scholar
  14. 14.
    M. Christensen, N. Lock, J. Overgaard, B·B. Iversen. J. Am. Chem. Soc. 128, 15657 (2006) doi: 10.1021/ja063695y PubMedCrossRefGoogle Scholar
  15. 15.
    J.A. McCormack and J.P. Fleurial, Materials Research Society Symposium Proceedings, 1991, p. 135.Google Scholar

Copyright information

© TMS 2009

Authors and Affiliations

  • Ali Saramat
    • 1
  • Eric S. Toberer
    • 1
  • Andrew F. May
    • 1
  • G. Jeffery Snyder
    • 1
  1. 1.Materials ScienceCalifornia Institute of TechnologyPasadenaUSA

Personalised recommendations