Thermoelectric properties of undoped p-type CoSb3 prepared by vertical Bridgman crystal growth and spark plasma sintering

Furuyama, S.; Iida, Tsutomu; Matsui, Shinsuke; Akasaka, Masayasu; Nishio, K.; Takanashi, Yoshifumi

doi:10.1016/j.jallcom.2005.07.057

Cited by 15 publications

(4 citation statements)

References 10 publications

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“…A value of 2.7 mΩ·m was observed in the sample at 300 K which is similar to the value reported by other authors [17]. The reported values for CoSb 3 resistivity at room temperature differ by three orders of magnitude, as reported by Furuyama et al [18], from 10 −1 to 10 −4 Ω·m. Samples with Sb-deficiency tends to present higher electrical resistivity, due to changes on the band structure caused by point variations of non-stoichiometry and defect structure [11].…”

Section: Resultssupporting

confidence: 89%

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

et al. 2017

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The effect of native defects originated by a non-stoichiometric variation of composition in CoSb3 on I-V curves and Hall effect was investigated. Hysteretic and a non-linear behavior of the I-V curves at cryogenic temperatures were observed; the non-linear behavior originated from the Poole-Frenkel effect, a field-dependent ionization mechanism that lowers Coulomb barriers and increases emission of charge carriers, and the hysteresis was attributed to the drastic decrease of specific heat which produces Joule heating at cryogenic temperatures. CoSb3 is a narrow gap semiconductor and slight variation in the synthesis process can lead to either n- or p-type conduction. The Sb-deficient CoSb3 presented an n-type conduction. Using a single parabolic model and assuming only acoustic-phonon scattering the charge transport properties were calculated at 300 K. From this model, a carrier concentration of 1.18 × 1018 cm−3 and a Hall factor of 1.18 were calculated. The low mobility of charge carriers, 19.11 cm2/V·s, and the high effective mass of the electrons, 0.66 m0, caused a high resistivity value of 2.75 × 10−3 Ω·m. The calculated Lorenz factor was 1.50 × 10−8 V2/K2, which represents a decrease of 38% over the degenerate limit value (2.44 × 10−8 V2/K2).

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Section: Resultssupporting

confidence: 89%

Effect of Native Defects on Transport Properties in Non-Stoichiometric CoSb3

et al. 2017

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“…Recently CoSb 3 -based skutterudite compound is regarded as one of the most promising materials to construct TE device working at intermediate temperature region (500-800 C), because of its relatively low thermal conductivity and high electrical conductivity. 9,10) However, as the key technology for fabricating TE device, the joining of metal electrode and CoSb 3 material is still a difficult problem. Nowadays, molybdenum (Mo) disk is chosen as electrodes due to its high electrical conductivity and thermal conductivity, and thermal expansion coefficient closing to that of CoSb 3 .…”

Section: Introductionmentioning

confidence: 99%

Modeling Temperature Gradient Evolution of CoSb<SUB>3</SUB> Material for Thermoelectric Devices during Spark Plasma Sintering

Cai

Zhao

et al. 2009

Mater. Trans.

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The temperature distribution and evolution of Mo/Ti/CoSb 3 materials used as thermoelectric couples of devices during spark plasma sintering were simulated by finite element method, and the results agree well with the die interior temperature measured by thermocouple. The sample and punches have higher temperature in whole sintering process, the highest temperature region is existed in CoSb 3 region, and the radial temperature gradient in CoSb 3 region is obvious. It was confirmed by experiments that the temperature gradient in sample results in non-uniform microstructure and thermal conductivity difference. The temperature gradient increases with decreasing thermal conductivity and increasing electrical resistivity of CoSb 3 -based compound, from the point of view of the thermal conductivity and electrical resistivity, respectively, the optimization method of the combined mechanical property and thermoelectric property of CoSb 3 -based compound was proposed.

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“…The conventional approaches [5][6][7] to solidstate synthesis have been proved to be successful, but can be slowly and time consuming. Recently, high pressure technology as a potentially tool to increase the rate of discovery of useful materials has spread all over the world [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%