Thermoelectric properties of Bi2O2Se single crystals
| Autor: | Zhefeng Lou, Tao Wang, Wanghua Hu, Xiaohui Yang, Xiao Lin, Jialu Wang, Zhuokai Xu |
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| Rok vydání: | 2021 |
| Předmět: |
Condensed Matter - Materials Science
Electron mobility Materials science Physics and Astronomy (miscellaneous) Phonon scattering Condensed matter physics Mean free path Scattering Phonon Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences chemistry.chemical_element Bismuth Thermal conductivity chemistry Thermoelectric effect |
| Zdroj: | Applied Physics Letters. 119:081901 |
| ISSN: | 1077-3118 0003-6951 |
| Popis: | Bismuth oxyselenide (Bi$_2$O$_2$Se) attracts great interest as a potential n-type complement to p-type thermoelectric oxides in practical applications. Previous investigations were generally focused on polycrystals. Here, we performed a study on the thermoelectric properties of Bi$_2$O$_2$Se single crystals. Our samples exhibit electron mobility as high as 250 cm$^2.$V$^{-1}$.s$^{-1}$ and thermal conductivity as low as $2$ W.m$^{-1}$.K$^{-1}$ near room temperature. The maximized figure of merit is yielded to be 0.188 at 390 K, higher than that of polycrystals. Consequently, a rough estimation of the phonon mean free path ($\ell_\textrm{ph}$) from the kinetic model amounts to 12 $\r{A}$ at 390 K and follows a $T^{-1}$ behavior. An extrapolation of $\ell_\textrm{ph}$ to higher temperatures indicates that this system approaches the Ioffe-Regel limit at about 1100 K. In light of the phonon dispersions, we argue that the ultralow $\ell_\textrm{ph}$ is attributed to intense anharmonic phonon-phonon scattering, including Umklapp process and acoustic to optical phonon scattering. Our results suggest that single crystals provide a further improvement of thermoelectric performance of Bi$_2$O$_2$Se. Comment: 6 pages, 4 figures |
| Databáze: | OpenAIRE |
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