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 language | English |
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Article number | 025116 |
Journal | Journal of Applied Physics |
Volume | 122 |
Issue number | 2 |
Number of pages | 6 |
ISSN | 0021-8979 |
DOIs | |
Publication status | Published - 2017 |