Achieving superior thermoelectric transport in bismuth antimony telluride thin films via orientation and microstructure regulation

The electron-phonon transport properties of bismuth telluride-based thermoelectric materials are significantly influenced by crystallographic orientation and microstructure engineering. Thin-film materials are proper candidates for the study of structure-property relationship due to abundant microst...

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Bibliographic Details
Main Authors: Qu Youyang, Zhao Bing, Zhao Weiyun, Deng Yuan
Format: Article
Language:English
Published: Science Press 2025-04-01
Series:National Science Open
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Online Access:https://www.sciengine.com/doi/10.1360/nso/20250008
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Summary:The electron-phonon transport properties of bismuth telluride-based thermoelectric materials are significantly influenced by crystallographic orientation and microstructure engineering. Thin-film materials are proper candidates for the study of structure-property relationship due to abundant microstructures. However, comprehensive studies on thin-film thermoelectric materials remain insufficient. Here, we synthesize p-type Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> thin films via magnetron sputtering and followed by heat treatment. Preferential growth orientation of thin films exhibits a strong dependence on deposition conditions, allowing targeted orientation engineering through process parameter optimization. A high sputtering pressure of <sc>3 Pa</sc> produces Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> thin films with preferred in-plane orientation. The post-heat treatment enables precise regulation of electron-phonon coupling efficiency by engineering defect configurations. The dislocation density was reduced after annealing, and anti-site defects can also be tuned to optimized carrier concentration and mobility. After the heat annealing process under 400°C, a super high zT value of 1.49 was achieved at <sc>313 K</sc> in Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> thin film.
ISSN:2097-1168