  Chromium-based nitrides are used in hard, resilient coatings, and show
promise for thermoelectric applications due to their combination of structural,
thermal, and electronic properties. Here, we investigated the electronic
structures and chemical bonding correlated to the thermoelectric properties of
epitaxially grown chromium-based multicomponent nitride Cr(Mo,V)Nx thin films.
Due to minuscule N vacancies, finite population of Cr 3d and N 2p states appear
at the Fermi level and diminishes the band opening for Cr0.51N0.49.
Incorporating holes by alloying V in N deficient CrN matrix results in enhanced
thermoelectric power factor with marginal change in the charge transfer of Cr
to N compared to Cr0.51N0.49. Further alloying Mo isoelectronic to Cr increases
the density of states across the Fermi level due to hybridization of the (Cr,
V) 3d and Mo 4d-N 2p states in Cr(Mo,V)Nx. The hybridization effect with
reduced N 2p states off from stoichiometry drives the system towards metal like
electrical resistivity and reduction in Seebeck coefficient compensating the
overall power factor still comparable to Cr0.51N0.49. The N deficiency also
depicts a critical role in reduction of the charge transfer from metal to N
site. The present work envisages ways for enhancing thermoelectric properties
through electronic band engineering by alloying and competing effects of N
vacancies.
