Thermoelectric Properties of In-Doped Cu2ZnGeSe4

Chetty, R and Bali, A and Femi, OE and Chattopadhyay, K and Mallik, RC (2016) Thermoelectric Properties of In-Doped Cu2ZnGeSe4. In: JOURNAL OF ELECTRONIC MATERIALS, 45 (3). pp. 1625-1632.

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Abstract

Recently, much research has been focused on finding new thermoelectric materials. Cu-based quaternary chalcogenides that belong to A(2)BCD(4) (A = Cu; B = Zn, Cd; C = Sn, Ge; D = S, Se, Te) are wide band gap materials and one of the potential thermoelectric materials due to their complex crystal structures. In this study, In-doped quaternary compounds Cu2ZnGe1-xInxSe4 (x = 0, 0.025, 0.05, 0.075, 0.1) were prepared by a solid state synthesis method. Powder x-ray diffraction patterns of all the samples showed a tetragonal crystal structure (space group I-42m) of the main phase with a trace amount of impurity phases, which was further confirmed by Rietveld analysis. The elemental composition of all the samples showed a slight deviation from the nominal composition with the presence of secondary phases. All the transport properties were measured in the temperature range 373-673 K. The electrical resistivity of all the samples initially decreased up to similar to 470 K and then increased with increase in temperature upto 673 K, indicating the transition from semiconducting to metallic behavior. Positive Seebeck coefficients for all the samples revealed that holes are the majority carriers in the entire temperature range. The substitution of In3+ on Ge4+ introduces holes and results in the decrease of resistivity as well as the Seebeck coefficient, thereby leading to the optimization of the power factor. The lattice thermal conductivity of all the samples decreased with increasing temperature, indicating the presence of phonon-phonon scattering. As a result, the thermoelectric figure of merit (zT) of the doped sample showed an increase as compared to the undoped compound.

Item Type:	Journal Article
Publication:	JOURNAL OF ELECTRONIC MATERIALS
Publisher:	SPRINGER
Additional Information:	Copy right for this article belongs to the SPRINGER, 233 SPRING ST, NEW YORK, NY 10013 USA
Keywords:	Thermoelectric properties; x-ray diffraction; scanning electron microscopy; phase transformation
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Apr 2016 05:33
Last Modified:	02 Apr 2016 05:33
URI:	http://eprints.iisc.ac.in/id/eprint/53587

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