Vishwakarma, Avinash and Chauhan, Nagendra S. and Bhardwaj, Ruchi and Johari, Kishor Kumar and Dhakate, Sanjay R. and Gahtori, Bhasker and Bathula, Sivaiah (2020) Melt-Spun SiGe Nano-Alloys: Microstructural Engineering Towards High Thermoelectric Efficiency. Journal of Electronic Materials , 50 (1). pp. 364-374. ISSN 0361-5235

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Silicon-germanium (SiGe) alloys are prominent high-temperature thermoelectric (TE) materials used as a powering source for deep space applications. In this work, we employed rapid cooling rates for solidification by melt-spinning and rapid heating rates for bulk consolidation employing spark plasma sintering to synthesize high-performance p-type SiGe nano-alloys. The current methodology exhibited a TE figure-of-merit (ZT) approximate to 0.94 at 1123 K for a higher cooling rate of similar to 3.0 x 10(7) K/s. This corresponds to approximate to 88% enhancement in ZT when compared with currently used radioisotope thermoelectric generators (RTGs) in space flight missions, approximate to 45% higher than pressure-sintered p-type alloys, which results in a higher output power density, and TE conversion efficiency (eta) approximate to 8% of synthesized SiGe nano-alloys estimated using a cumulative temperature dependence (CTD) model. The ZT enhancement is driven by selective scattering of phonons rather than of charge carriers by the high density of grain boundaries with random orientations and induced lattice-scale defects, resulting in a substantial reduction of lattice thermal conductivity and high power factor. The TE characteristics of synthesized alloys presented using the constant property model (CPM) and CTD model display their high TE performance in high-temperature regimes along with wide suitability of segmentation with different mid-temperature TE materials.

Item Type: Article
Additional Information: Copyright for this article belongs to M/s Springer.
Subjects: Engineering
Engineering > Electronics and Electrical Engineering
Materials Science
Applied Physics/Condensed Matter
Depositing User: Mr. Yogesh Joshi
Date Deposited: 29 Mar 2022 10:19
Last Modified: 29 Mar 2022 10:19

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