Compositional Fluctuations Locked by Athermal Transformation Yielding High Thermoelectric Performance in GeTe
Journal
Advanced Materials
Journal Volume
33
Journal Issue
1
Start Page
2005612
ISSN
09359648
Date Issued
2021
Author(s)
Tsai, Yi-Fen
Wei, Pai-Chun
Chang, Liuwen
Wang, Kuang-Kuo
Yang, Chun-Chuen
Lai, Yen-Chung
Hsing, Cheng-Rong
Wei, Ching-Ming
He, Jian
Snyder, G. Jeffrey
Abstract
Phase transition in thermoelectric (TE) material is a double-edged sword—it is undesired for device operation in applications, but the fluctuations near an electronic instability are favorable. Here, Sb doping is used to elicit a spontaneous composition fluctuation showing uphill diffusion in GeTe that is otherwise suspended by diffusionless athermal cubic-to-rhombohedral phase transition at around 700 K. The interplay between these two phase transitions yields exquisite composition fluctuations and a coexistence of cubic and rhombohedral phases in favor of exceptional figures-of-merit zT. Specifically, alloying GeTe by Sb2Te3 significantly suppresses the thermal conductivity while retaining eligible carrier concentration over a wide composition range, resulting in high zT values of >2.6. These results not only attest to the efficacy of using phase transition in manipulating the microstructures of GeTe-based materials but also open up a new thermodynamic route to develop higher performance TE materials in general. © 2020 Wiley-VCH GmbH
Subjects
displacive phase transformation
germanium telluride
thermoelectric figure of merit
Publisher
Wiley-VCH Verlag
Description
論文編號: 2005612
Type
journal article