Phase Composition and Thermoelectric Properties of Epitaxial CrMoVN Thin Films

Abstract

Thin films of CrMoVN are deposited on c‐plane sapphire (Al2O3 (0001)) by direct current reactive magnetron sputtering, to investigate the effects of Mo and V addition to CrN‐based films. All films grow epitaxially, but Mo incorporation affects the crystal structure and nitrogen content. All films in the CrMoVN series are understoichiometric in nitrogen, but largely retain the NaCl B1 structure of stoichiometric CrN films. Addition of vanadium increases the phase‐stability range of the cubic phase, allowing for higher solubility of Mo than what has previously been reported for cubic CrN. The Seebeck coefficient and electrical resistivity are greatly affected by the alloying, showing a decrease of the Seebeck coefficient along with a decrease in resistivity. Cr0.83Mo0.11V0.06Nz shows a 70% increase in power factor (S2σ = 0.22 mW m−1 K−2) compared to the reference CrNz (S2σ = 0.13 mW m−1 K−2).

Keywords

• alloys
• chromium
• CrN
• epitaxy
• nitrides
• thermoelectrics