Improving thermoelectric efficiency of multilayer ScN/Sc1-xNbxN heterostructures by Nb doping

Joris More-Chevalier1,, Urszula. D. Wdowik2,, Jiří Martan3, Xavier Portier4, Stanislav Cichoň1, Esther de Prado1, Petr Levinský1, Ladislav Fekete1, Jan Pokorný1, Dejan Prokop1,5, Petr Hruška1,5, Markéta Jarošová1, Jan Kejzlar1, Dominik Legut2,5, Michal Novotný1, Ján Lančok1

1Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Praha 8, Czech Republic

2IT4Innovations, VSB - Technical University of Ostrava, 17. listopadu 2172/15, CZ 708 00 Ostrava-Poruba, Czech Republic

3New Technologies Research Centre (NTC), University of West Bohemia, Univerzitni 8, 301 00 Plzeň, Czech Republic

4CIMAP Normandie Université, ENSICAEN, UNICAEN, CEA, UMR CNRS 6252, 6 Boulevard Maréchal Juin, 14050 Caen Cedex 4, France

5Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic

The thermoelectric properties of ScN/Sc1-xNbxN multilayers deposited on MgO (001) substrates were investigated using a combined experimental and theoretical approach based on the density functional theory. Four multilayers were prepared, exhibiting total Nb percentages of 0.4%, 1.2%, 1.8%, and 4.8% atomic ratio in the samples. Structural characterization confirmed the epitaxial growth of multilayers with sharp interfaces. Thermoelectric measurements showed an enhancement of the Seebeck coefficient and a reduction in thermal conductivity with Nb-doped ScN interlayers. The figure of merit (ZT) was potentially increased to over 0.3. This improvement highlights the promise of this approach for enhancing the thermoelectric performance of scandium nitride.

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Figure 1: In (a), the 2θ/ω scans of each ScN-Nb film in the 2θ range from 30° to 100°. The inserts include the 002 rocking curves of each film, including the FWHM, which are equal to 0.576°, 0.510°, 0.593°, and 0.698° for the multilayer films containing 0.4%, 1.2%, 1.8%, and 4.8% of Nb, respectively. In (b), 111 pole figure of the ScN-Nb 1.8%.