Reduction of the thermal conductivity of the thermoelectric material ScN by Nb alloying

Nina Tureson, Ngo Van Nong, Daniele Fournier, Niraj Singh, Somnath Acharya, Susann Schmidt, Laurent Belliard, Ajay Soni, Arnaud le Febvrier, Per Eklund

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Abstract

ScN-rich (Sc,Nb)N solid solution thin films have been studied, motivated by the promising thermoelectric properties of ScN-based materials. Cubic Sc1-xNbxN films for 0 ≤ x ≤ 0.25 were epitaxially grown by DC reactive magnetron sputtering on a c-plane sapphire substrate and oriented along the (111) orientation. The crystal structure, morphology, thermal conductivity, and thermoelectric and electrical properties were investigated. The ScN reference film exhibited a Seebeck coefficient of −45 μV/K and a power factor of 6 × 10−4 W/m K2 at 750 K. Estimated from room temperature Hall measurements, all samples exhibit a high carrier density of the order of 1021 cm−3. Inclusion of heavy transition metals into ScN enables the reduction in thermal conductivity by an increase in phonon scattering. The Nb inserted ScN thin films exhibited a thermal conductivity lower than the value of the ScN reference (10.5 W m−1 K−1) down to a minimum value of 2.2 Wm−1 K−1. Insertion of Nb into ScN thus resulted in a reduction in thermal conductivity by a factor of ∼5 due to the mass contrast in ScN, which increases the phonon scattering in the material.
Original languageEnglish
Article number025116
JournalJournal of Applied Physics
Volume122
Issue number2
Number of pages6
ISSN0021-8979
DOIs
Publication statusPublished - 2017

Bibliographical note

Copyright (2017) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 122(2), [025116] and may be found at http://aip.scitation.org/doi/10.1063/1.4993913.

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