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Vol.61, No.3, 206 ~ 213, 2023
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| Title |
| Electrical, Thermal, and Thermoelectric Transport Properties of Co-Doped n-type Cu0.008Bi2Te2.6Se0.4 Polycrystalline Alloys |
| 박옥민 Okmin Park , 김태완 Taewan Kim , 허민수 Minsu Heo , 박상정 Sang Jeong Park , 이세웅 Se Woong Lee , 조현규 Hyun Kyu Cho , 김상일 Sang-il Kim |
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| Abstract |
| Bi2Te3-based alloys have been extensively studied as thermoelectric materials near room temperature. In this study, the electrical, thermal, and thermoelectric transport properties of a series of Co-doped n-type Cu0.008Bi2Te2.6Se0.4 polycrystalline alloys (Cu0.008Bi2-xCoxTe2.6Se0.4, x = 0, 0.03, 0.06, 0.09 and 0.12) are investigated. The electrical conductivity of the Cu0.008Bi1.97Co0.03Te2.6Se0.4 (x = 0.03) sample was significantly enhanced, by 34%, to 1199 S/cm compared to 793 S/cm of the pristine Cu0.008Bi2Te2.6Se0.4 (x = 0) sample at 300 K, and gradually decreased to 906 S/cm for x = 0.12 upon further doping. Power factors of the Co-doped samples decreased compared to the 3.26 mW/mK2 of the pristine Cu0.008Bi2Te2.6Se0.4 sample at 300 K. Meanwhile, the power factor of the Cu0.008Bi1.97Co0.03Te2.6Se0.4 (x = 0.03) sample became higher at 520 K. The lattice thermal conductivities of the Co-doped samples decreased due to additional point defect phonon scattering by the Co dopant. Consequently, the zT for the Cu0.008Bi1.97Co0.03Te2.6Se0.4 alloy at 520 K was 0.83, which is approximately 15% larger than that of pristine Cu0.008Bi2Te2.6Se0.4, while the zT of the Cu doped samples at 300 K was smaller than that of the pristine Cu0.008Bi2Te2.6Se0.4 sample. Electrical transport properties of the Co-doped Cu0.008Bi2-xCoxTe2.6Se0.4 samples were analyzed by experimental phenomenological parameters, including the density-of-state, effective mass, weighted mobility, and quality factor.
(Received 5 December, 2022; Accepted 20 December, 2022) |
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| Key Words |
| thermoelectric, Bi2Te3, doping |
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