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Home  >  Journal list  >  MATERIALS TRANSACTIONS  >  Vol.53  No.7 (2012)  >  pp.1212-1215

<<Previous article Vol.53  No.7 (2012)   pp.1212 - 1215 Next article>>

Effect of the Amount of Vacancies on the Thermoelectric Properties of Cu–Ga–Te Ternary Compounds

Theerayuth Plirdpring1) 2), Ken Kurosaki1), Atsuko Kosuga3), Manabu Ishimaru4), Adul Harnwunggmoung1) 2), Tohru Sugahara1), Yuji Ohishi1), Hiroaki Muta1), Shinsuke Yamanaka1) 5)
1) Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University 2) Thermoelectric and Nanotechnology Research Center, Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi 3) Nanoscience and Nanotechnology Research Center, Research Organization for the 21st Century, Osaka Prefecture University 4) Institute of Scientific and Industrial Research, Osaka University 5) Research Institute of Nuclear Engineering, University of Fukui

The Cu–Ga–Te ternary compounds: Cu3Ga5Te9, Cu2Ga4Te7, CuGa3Te5, CuGa5Te8, and CuGaTe2 have zinc-blende or chalcopyrite structure. The compounds except for CuGaTe2 contain vacancies in the cation site due to the valence mismatch between cation and anion, and the vacancy concentration is different between these compounds. Here we investigated the effect of the amount of vacancies on the thermoelectric (TE) properties of the Cu–Ga–Te ternary compounds. At room temperature, the presence of vacancies reduced the Hall mobility (μH) and the lattice thermal conductivity (κlat), showing that the vacancies scattered both carriers and phonons. It was found that the decreasing rate of the μH was larger than that of the κlat. Therefore, the presence of vacancies degraded the TE performance of the Cu–Ga–Te ternary compounds. In other words, CuGaTe2 without vacancies would show the best TE figure of merit. The room temperature ZT values for Cu3Ga5Te9, Cu2Ga4Te7, CuGa3Te5, CuGa5Te8, and CuGaTe2 were 2.0 × 10−2, 2.4 × 10−2, 8.9 × 10−3, 1.3 × 10−2, and 5.6 × 10−3, respectively.

thermoelectric, copper–gallium–tellurium compounds, vacancy, thermal conductivity, electrical resistivity, Seebeck coefficient

Received: September 13, 2011
Accepted: February 21, 2012 , Published online: June 25, 2012
Copyright © 2012 The Thermoelectrics Society of Japan



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