Thermoelectric performance of co-doped SnTe with resonant levels

Min Zhou, Zachary M. Gibbs, Heng Wang*, Yemao Han, Laifeng Li, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Some group III elements such as Indium are known to produce the resonant impurity states in IV-VI compounds. The discovery of these impurity states has opened up new ways for engineering the thermoelectric properties of IV-VI compounds. In this work, resonant states in SnTe were studied by co-doping with both resonant (In) and extrinsic (Ag, I) dopants. A characteristic nonlinear relationship was observed between the Hall carrier concentration (nH) and extrinsic dopant concentration (NI, NAg) in the stabilization region, where a linear increase of dopant concentration does not lead to linear response in the measured nH. Upon substituting extrinsic dopants beyond a certain amount, the nH changed proportionally with additional dopants (Ag, I) (the doping region). The Seebeck coefficients are enhanced as the resonant impurity is introduced, whereas the use of extrinsic doping only induces minor changes. Modest zT enhancements are observed at lower temperatures, which lead to an increase in the average zT values over a broad range of temperatures (300-773 K). The improved average zT obtained through co-doping indicates the promise of fine carrier density control in maximizing the favorable effect of resonant levels for thermoelectric materials.

Original languageEnglish (US)
Article number042102
JournalApplied Physics Letters
Volume109
Issue number4
DOIs
StatePublished - Jul 25 2016

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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