Thermoelectric performance of co-doped SnTe with resonant levels
- Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd. Pasadena, California 91125 (United States)
- Materials Science, California Institute of Technology, 1200 California Blvd., Pasadena, California 91125 (United States)
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 (n{sub H}) and extrinsic dopant concentration (N{sub I}, N{sub Ag}) in the stabilization region, where a linear increase of dopant concentration does not lead to linear response in the measured n{sub H}. Upon substituting extrinsic dopants beyond a certain amount, the n{sub H} 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.
- OSTI ID:
- 22594439
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 4 Vol. 109; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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