Optimized thermoelectric performance of Bi2Te3 nanowires

H. Y. Lv; H. J. Liu; J. Shi; X. F. Tang; C. Uher

doi:10.1039/C3TA10804J

Optimized thermoelectric performance of Bi₂Te₃nanowires

H. Y. Lv,^a H. J. Liu,*^a J. Shi,^a X. F. Tang^b and C. Uher^c

* Corresponding authors

^a Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
E-mail: phlhj@whu.edu.cn
Fax: +86-27-68752569
Tel: +86-27-68754613

^b State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China

^c Department of Physics, University of Michigan, Ann Arbor, MI, USA

Abstract

The structural and electronic properties of a series of stoichiometric Bi₂Te₃ nanowires with two growth orientations [110] and [210] are studied by using density functional calculations. Our results indicate that the nanowires with [110] orientation are energetically more favorable than those with [210] orientation. All the investigated Bi₂Te₃ nanowires are found to be semiconducting and the band gaps of [110] nanowires monotonically increase with the decreasing cross-sectional width. For the [210] orientation, however, the band gaps exhibit an interesting width-dependent even–odd oscillation behavior. The electronic transport properties of these nanowires are then evaluated by using the semi-classical Boltzmann theory with the relaxation time approximation. For the phonon transport, the lattice thermal conductivity is predicted by using the non-equilibrium molecule dynamics simulations. Our theoretical calculations suggest that the thermoelectric performance of Bi₂Te₃ nanowires can be optimized at appropriate carrier concentration with particular orientation and cross-sectional size. The figure of merit (ZT value) can reach as high as 2.3 at 300 K and 2.5 at 350 K for the [210] nanowire with the width N = 5.

Article information

https://doi.org/10.1039/C3TA10804J

Article type

Paper

Submitted

25 Feb 2013

Accepted

09 Apr 2013

First published

10 Apr 2013

Download Citation

J. Mater. Chem. A, 2013,1, 6831-6838

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Optimized thermoelectric performance of Bi₂Te₃ nanowires

H. Y. Lv, H. J. Liu, J. Shi, X. F. Tang and C. Uher, J. Mater. Chem. A, 2013, 1, 6831 DOI: 10.1039/C3TA10804J

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Journal of Materials Chemistry A