Thermoelectric Properties and Structural Variations in Bi2Te3-xSx Crystals

Published

February 23, 2012

Author(s)

Winnie K. Wong-Ng, Howard Joress, Joshua B. Martin, Peter Zavalij, Yonggao Y. Yan, Jihui Yang

Abstract

We have successfully correlated the thermoelectric properties, structure and compositional variations of a Bi2Te3-xSx single crystal using a custom-designed, non-destructive, high-throughput Seebeck coefficient screening tool, together with a single crystal X-ray diffraction system. Bi2Te3-xSx consists of repeated quintuple layers of atom groups (Te/S-Bi-S-Bi-Te/S) stacked along the c-axis, with weak van der Waals forces between each group via the outer Te/S layers. The binding strength of the crystal is apparently maximized when S completely occupies the inner Te layer of quintuple layers of the Bi2Te3 structure, but only partially substitutes in the outer Te layer. A small gradient of Te/S concentration was found as a function of distance along the long axis of the crystal. As Bi2Te3-xSx is a n-type semiconductor, the greater the S concentration (resulting in a decrease in the hole concentration), the lower the Seebeck coefficient and the higher the carrier density of Bi2Te3-xSx, as expected from a rigid band semiconductor model.

Citation

Applied Physics Letters

Volume

100

Pub Type

Journals

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DOI Link

Keywords

Bi2(Te, S)3 crystals, composition-structure-property relationships, Seebeck coefficient screening tool, thermoelectric material

Citation

Wong-Ng, W. , Joress, H. , Martin, J. , Zavalij, P. , Yan, Y. and Yang, J. (2012), Thermoelectric Properties and Structural Variations in Bi2Te3-xSx Crystals, Applied Physics Letters, [online], https://doi.org/10.1063/1.3688485 (Accessed December 11, 2024)