Heavy element doping for enhancing thermoelectric properties of nanostructured zinc oxide

ZnO is a high melting point, high charge carrier mobility semiconductor with potential as a thermoelectric material, but its high thermal conductivity Kappa is the limiting factor for increasing the thermoelectric figure of merit ZT. Here, we demonstrate that doping ZnO with heavy elements can signi...

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Bibliographic Details
Published in:RSC advances 2014, Vol.4 (13), p.6363-6368
Main Authors: Jood, Priyanka, Mehta, Rutvik J., Zhang, Yanliang, Borca-Tasciuc, Theo, Dou, Shi Xue, Singh, David J., Ramanath, Ganpati
Format: Article
Language:English
Subjects:
Charge carriers
Doping
Heavy elements
Nanomaterials
Nanostructure
Semiconductors
Thermoelectricity
Zinc oxide
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Summary:ZnO is a high melting point, high charge carrier mobility semiconductor with potential as a thermoelectric material, but its high thermal conductivity Kappa is the limiting factor for increasing the thermoelectric figure of merit ZT. Here, we demonstrate that doping ZnO with heavy elements can significantly enhance ZT. Indium doping leads to ultralow Kappa similar to 3 W m super(-1) K super(-1) and a high power factor alpha super(2) sigma similar to 1.230 10 super(-3) W m super(-1) K super(-2), yielding ZT sub(1000K) similar to 0.45 that is similar to 80% higher than non-nanostructured In-Zn-O alloys. Although Bi doping also yields a high Seebeck coefficient of alpha sub(300K) similar to 500 mu V K super(-1), Bi segregation, grain growth and defect complexing are unfavorable for increasing ZT. Thus, besides increased impurity scattering of phonons, the concurrence of nanostructuring and charge carrier concentration control is key to ZT enhancement. Our results open up a new means to realize high ZT thermoelectric nanomaterials based on ZnO.
ISSN:2046-2069
2046-2069
DOI:10.1039/c3ra46813e