Manipulation of ionized impurity scattering for achieving high thermoelectric performance in n-type Mg
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Author(s)
Mao, Jun
Shuai, Jing
Song, Shaowei
Wu, Yixuan
Dally, Rebecca
Zhou, Jiawei
Liu, Zihang
Sun, Jifeng
Zhang, Qinyong
dela Cruz, Clarina
Date Issued
September 2017
Journal
Proceedings of the National Academy of Sciences
Publisher
National Academy of Sciences (U.S.)
Citation
Mao, Jun et al. “Manipulation of Ionized Impurity Scattering for Achieving High Thermoelectric Performance in n-Type Mg3Sb2-Based Materials.” Proceedings of the National Academy of Sciences 114, 40 (September 2017): 10548–10553 © 2017 The Authors
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Final published version
Abstract
Achieving higher carrier mobility plays a pivotal role for obtaining potentially high thermoelectric performance. In principle, the carrier mobility is governed by the band structure as well as by the carrier scattering mechanism. Here, we demonstrate that by manipulating the carrier scattering mechanism in n-type Mg[subscript 3]Sb[subscript 2 ]-based materials, a substantial improvement in carrier mobility, and hence the power factor, can be achieved. In this work, Fe, Co, Hf, and Ta are doped on the Mg site of Mg[subscript 3.2]Sb[subscript 1.5]Bi[subscript 0.49]Te [subscript 0.01], where the ionized impurity scattering crosses over to mixed ionized impurity and acoustic phonon scattering. A significant improvement in Hall mobility from ∼16 to ∼81 cm 2 ·V[superscript −1]·s[superscript − 1] is obtained, thus leading to a notably enhanced power factor of ∼13 μW·cm [superscript −1]·K [superscript −2] from ∼5 μW·cm[superscript −1]·K[superscript −2]. A simultaneous reduction in thermal conductivity is also achieved. Collectively, a figure of merit (ZT) of ∼1.7 is obtained at 773 K in Mg[subscript 3.1]Co[subscript 0.1]Sb[subscript 1.5]Bi[subscript 0.49]Te [subscript 0.01]. The concept of manipulating the carrier scattering mechanism to improve the mobility should also be applicable to other material systems. Keywords: thermoelectric; carrier scattering mechanism; ionized impurity scattering; n-type; Mg[subscript 3]Sb[subscript 2]; defects
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1073/PNAS.1711725114
