Thermoelectric properties of Zn doped Cu2SnSe3

Raju, Ch and Falmbigl, M and Rogl, P and Heinrich, P and Royanian, E and Bauer, E and Mallik, Ramesh Chandra (2014) Thermoelectric properties of Zn doped Cu2SnSe3. In: MATERIALS CHEMISTRY AND PHYSICS, 147 (3). pp. 1022-1028.

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Abstract

Zn doped ternary compounds Cu2ZnxSn1-xSe3 (x = 0, 0.025, 0.05, 0.075) were prepared by solid state synthesis. The undoped compound showed a monoclinic crystal structure as a major phase, while the doped compounds showed a cubic crystal structure confirmed by powder XRD (X-Ray Diffraction). The surface morphology and elemental composition analysis for all the samples were studied by SEM (Scanning Electron Microscopy) and EPMA (Electron Probe Micro Analyzer), respectively. SEM micrographs of the hot pressed samples showed the presence of continuous and homogeneous grains confirming sufficient densification. Elemental composition of all the samples revealed an off-stoichiometry, which was determined by EPMA. Transport properties were measured between 324 K and 773 K. The electrical resistivity decreased up to the samples with Zn content x = 0.05 in Cu2ZnxSn1-xSe3, and slightly increased in the sample Cu2Zn0.075Sn0.925Se3. This behavior is consistent with the changes in the carrier concentration confirmed by room temperature Hall coefficient data. Temperature dependent electrical resistivity of all samples showed heavily doped semiconductor behavior. All the samples exhibit positive Seebeck coefficient (S) and Hall coefficient indicating that the majority of the carriers are holes. A linear increase in Seebeck coefficient with increase in temperature indicates the degenerate semiconductor behavior. The total thermal conductivity of the doped samples increased with a higher amount of doping, due to the increase in the carrier contribution. The total and lattice thermal conductivity of all samples showed 1/1 dependence, which points toward the dominance of phonon scattering at high temperatures. The maximum 1/TZF = 0.48 at 773 K was obtained for the sample Cu2SnSe3 due to a low thermal conductivity compared to the doped samples. (C) 2014 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	MATERIALS CHEMISTRY AND PHYSICS
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	26 Sep 2014 10:28
Last Modified:	26 Sep 2014 10:28
URI:	http://eprints.iisc.ac.in/id/eprint/49956

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