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Thermoelectricity of Al-doped ZnO at different carrier concentrations

Published online by Cambridge University Press:  31 January 2011

Yoshiaki Kinemuchi*
Affiliation:
National Institute of Advanced Industrial Science and Technology (AIST), Advanced Manufacturing Research Institute, Shimoshidami, Moriyama, Nagoya 463-8560, Japan
Chihiro Ito
Affiliation:
National Institute of Advanced Industrial Science and Technology (AIST), Advanced Manufacturing Research Institute, Shimoshidami, Moriyama, Nagoya 463-8560, Japan
Hisashi Kaga
Affiliation:
National Institute of Advanced Industrial Science and Technology (AIST), Advanced Manufacturing Research Institute, Shimoshidami, Moriyama, Nagoya 463-8560, Japan
Tomohiro Aoki
Affiliation:
Sinto V-Cerax Ltd., 3-1 Honohara, Toyokawa 442-8505, Japan
Koji Watari
Affiliation:
National Institute of Advanced Industrial Science and Technology (AIST), Advanced Manufacturing Research Institute, Shimoshidami, Moriyama, Nagoya 463-8560, Japan
*
a)Address all correspondence to this author. e-mail: y.kinemuchi@aist.go.jp
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Abstract

Optimization of the carrier concentration is a key to improve the power factor of thermoelectricity. The carrier concentration of sintered zinc oxides was primarily controlled by impurity doping of aluminum and secondarily adjusted by defect concentration by varying the oxygen partial pressure in the range of 101 to 104 Pa. The resultant carrier concentration measured at room temperature ranged from 1 to 1.8 × 1020 cm−3, which drastically modified the thermoelectricity. The Jonker plot of the measured Seebeck coefficient and conductivity revealed deviation of the slope from k/e (where k is the Boltzmann constant and e is the elemental electric charge), which was attributed to a mobility variation with respect to the carrier concentration. The approach to estimating the optimum conductivity taking into account mobility variation is discussed. Finally, the optimum conductivity is estimated to be 1800 to 2000 S/cm for high-temperature operation (500 to 800 °C).

Type
Articles
Copyright
Copyright © Materials Research Society 2007

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References

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