1. Enhanced thermal stability of Bi2Te3-based alloys via interface engineering with atomic layer deposition
- Author
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Seong Keun Kim, Kwang-Chon Kim, Jinsang Kim, Ju-Young Kim, J.-S. Kang, Seung Hyub Baek, Sang-Soon Lim, Hansol Jeon, and Hyung Ho Park
- Subjects
010302 applied physics ,Materials science ,Interface engineering ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic layer deposition ,Coating ,0103 physical sciences ,Thermoelectric effect ,Materials Chemistry ,Ceramics and Composites ,engineering ,Thermal stability ,Sublimation (phase transition) ,Composite material ,0210 nano-technology - Abstract
The ease of Te sublimation from Bi2Te3-based alloys significantly deteriorates thermoelectric and mechanical properties via the formation of voids. We propose a novel strategy based on atomic layer deposition (ALD) to improve the thermal stability of Bi2Te3-based alloys via the encapsulation of grains with a ZnO layer. Only a few cycles of ZnO ALD over the Bi2Te2.7Se0.3 powders resulted in significant suppression of the generation of pores in Bi2Te2.7Se0.3 extrudates and increased the density even after post-annealing at 500 °C. This is attributed to the suppression of Te sublimation from the extrudates. The ALD coating also enhanced grain refinement in Bi2Te2.7Se0.3 extrudates. Consequently, their mechanical properties were significantly improved by the encapsulation approach. Furthermore, the ALD approach yields a substantial improvement in the figure-of-merit after the post-annealing. Therefore, we believe the proposed approach using ALD will be useful for enhancing the mechanical properties of Bi2Te3-based alloys without sacrificing thermoelectric performance.
- Published
- 2020
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