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Enhancement of ZT in Bi0.5Sb1.5Te3 Thin Film through Lattice Orientation Management

Authors :
Wei-Han Tsai
Cheng-Lung Chen
Ranganayakulu K. Vankayala
Ying-Hsiang Lo
Wen-Pin Hsieh
Te-Hsien Wang
Ssu-Yen Huang
Yang-Yuan Chen
Source :
Nanomaterials, Vol 14, Iss 9, p 747 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Thermoelectric power can convert heat and electricity directly and reversibly. Low-dimensional thermoelectric materials, particularly thin films, have been considered a breakthrough for separating electronic and thermal transport relationships. In this study, a series of Bi0.5Sb1.5Te3 thin films with thicknesses of 0.125, 0.25, 0.5, and 1 μm have been fabricated by RF sputtering for the study of thickness effects on thermoelectric properties. We demonstrated that microstructure (texture) changes highly correlate with the growth thickness in the films, and equilibrium annealing significantly improves the thermoelectric performance, resulting in a remarkable enhancement in the thermoelectric performance. Consequently, the 0.5 μm thin films achieve an exceptional power factor of 18.1 μWcm−1K−2 at 400 K. Furthermore, we utilize a novel method that involves exfoliating a nanosized film and cutting with a focused ion beam, enabling precise in-plane thermal conductivity measurements through the 3ω method. We obtain the in-plane thermal conductivity as low as 0.3 Wm−1K−1, leading to a maximum ZT of 1.86, nearing room temperature. Our results provide significant insights into advanced thin-film thermoelectric design and fabrication, boosting high-performance systems.

Details

Language :
English
ISSN :
20794991
Volume :
14
Issue :
9
Database :
Directory of Open Access Journals
Journal :
Nanomaterials
Publication Type :
Academic Journal
Accession number :
edsdoj.fa9837f3effc4f4aac99154f7ab7c0ee
Document Type :
article
Full Text :
https://doi.org/10.3390/nano14090747