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Vol.61, No.1, 38 ~ 46, 2023
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| Title |
| Approaches to Estimate the Magnitude of Phonon Scattering via Point Defects in Mo(Se1-xTex)2 Thermoelectric Alloys |
| 이유종 You-jong Lee , 김상일 Sang-il Kim , 황성미 Seong-mee Hwang , 김정연 Jeong-yeon Kim , 서원선 Won-seon Seo , 김현식 Hyun-sik Kim |
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| Abstract |
| One of the most popular routes used to improve the thermoelectric performance of materials is to suppress their lattice thermal conductivities. Thermoelectric performance is characterized by a figure-of-merit zT, which is defined as σS2T/(κe + κl), where the σ, S, T, κe, and κl are the electrical conductivity, Seebeck coefficient, temperature (in Kelvin), electronic thermal conductivity, and the lattice thermal conductivity, respectively. Among the variables in zT, the κl is the only variable that is independent of all other variables. In other words, reduction in κl guarantees zT improvement. Therefore, several different strategies to decrease κl have been introduced and implemented. Among the many κl reduction strategies, introducing point defects in the material by forming an alloy is particularly effective. Here, phonon scattering due to point defects in Mo(Se1-xTex)2 (x = 0.0, 0.25, 0.50, 0.75, 1.0) was studied using both the Debye-Callaway (DC) model and Callaway-von Baeyer (CvB) model. The advantages and disadvantages of using DC or CvB models are thoroughly discussed. When analyzing the effect of phonon scattering due to point defects, the CvB model is simpler and gives more information about the details of phonon scattering.
(Received 6 September, 2022; Accepted 26 September, 2022) |
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| Key Words |
| hermoelectric, lattice thermal conductivity, point defect, debye-callaway model, callaway-von baeyer model |
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