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Vol.61, No.6, 437 ~ 444, 2023
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| Title |
| Synthesis and Thermoelectric Properties of La-doped n-type Mg3SbBi Materials |
| 주성재 Sung-jae Joo , 손지희 Ji-hee Son , 장정인 Jeongin Jang , 민복기 Bok-ki Min , 김봉서 Bong-seo Kim |
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| Abstract |
| Mg3Sb2-based materials are very promising for thermoelectric applications at low temperatures, and are strong candidates to replace n-type Bi2Te3 for cooling and power generation. Substituting Sb atoms with chalcogen elements (S, Se, Te) is a typical method of n-type doping, while doping the Mg site with Group 3 elements (Y, Sc) and Lanthanides has also been studied. Unique advantages have been recently reported. In this study, a La-containing compound, LaSb, was used to fabricate n-type Mg3SbBi. The thermoelectric properties of polycrystalline Mg3LaxSbBi (0 ≤ x ≤ 0.02) were investigated after synthesis by sequential processes of arc melting, ball milling, and spark plasma sintering. Undoped Mg3SbBi is p-type with poor thermoelectric performance, and switched to n-type with La doping. The electron concentration of Mg3LaxSbBi increased linearly with La content x, reaching up to 9.4 × 1019 cm-3 at x = 0.02. The power factor and the figure of merit were also maximized in Mg3La0.02SbBi, reaching 1.8 mW m-1K-2 (573 K) and 0.89 (623 K), respectively. The lattice thermal conductivity decreased with increasing La content above ~500 K, and the minimum value of 0.73 W m-1K-1 was obtained in Mg3La0.02SbBi. This study shows that La doping using LaSb provides a reliable method for n-type doping of Mg3Sb2-based materials.
(Received 21 February, 2023; Accepted 9 March, 2023) |
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| Key Words |
| thermoelectric, Mg3SbBi, La doping, LaSb |
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