SnSe2 결함 도입으로 인한 SnSe의 고온 열전성능 증대 메커니즘

Translated title of the contribution: The Mechanism Behind the High zT of SnSe2 Added SnSe at High Temperatures

Kim JunSu, Hwang Seong-Mee, Park Hyunjin, Tang Yinglu, Seo Won-Seon, Ryu Chae Woo, Yang Heesun, Shin Weon Ho*, Kim Hyun-Sik*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

SnSe is a promising thermoelectric material due to its low toxicity, low thermal conductivity, and multiple valence band structures, which are ideal for high electronic transport properties. The multiple valence band structure has attracted many attempts to engineer the carrier concentration of the SnSe via doping, to place its fermi level at a position where the maximum number of valence bands can participate in the electronic transport. Up until now, ~5 × 1019 cm-3 was the highest carrier concentration achieved in SnSe via doping. Recently, introducing SnSe2 into SnSe was found to effectively increase the carrier concentration as high as ~6.5 × 1019 cm-3 (at 300 K) due to the generated Sn vacancies. This high carrier concentration at 300 K, combined with the reduction in lattice thermal conductivity due to SnSe2 micro-domains formed within the SnSe lattice, improved the thermoelectric performance (zT) of SnSe – xSnSe2 as high as ~2.2 at 773 K. Here, we analyzed the changes in the electronic band parameters of SnSe as a function of temperature with varying SnSe2 content using the Single Parabolic Band (SPB) model. According to the SPB model, the calculated density-of-states effective mass and the fermi level are changed with temperature in such a way that the Hall carrier concentration (nH) of the SnSe – xSnSe2 samples at 773 K coincides with the optimum nH where the theoretically maximum zT is predicted. To optimize the nH at high temperatures for the highest zT, it is essential to tune the 300 K nH and the rate of nH change with increasing temperature via doping.

Translated title of the contributionThe Mechanism Behind the High zT of SnSe2 Added SnSe at High Temperatures
Original languageKorean
Pages (from-to)857-866
Number of pages10
JournalJournal of Korean Institute of Metals and Materials
Volume61
Issue number11
DOIs
Publication statusPublished - 2023

Funding


This work was supported by the Basic Study and Interdisciplinary R&D Foundation Fund of the University of Seoul (2022) for Hyun-Sik Kim. This work was also financially supported by Basic Science Research Prog ram throug h the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2019R1A6A1A11055660, NRF-2015R1A6A1A03031833) for Won-Seon Seo and Heesun Yang . This work was also supported by the Technology Innovation Program RS-2022-00154720 funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea) for Weon Ho Shin.

Keywords

  • Carrier concentration
  • High-temperature zT
  • Power factor
  • Single Parabolic Band model
  • SnSe

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