Ternary carbide in metal matrix composites constitute a big challenge in the industry, and in this regard their surface treatment is one of the most important issues. Ternary carbide (Cu_xTi_yC_z, where x, y and z are integers) thin films are synthesized by magnetron sputtering and characterized with respect to the film depth. X-ray photoelectron spectroscopy (XPS) of Cu-2p and Ti-2p peaks shows the associated shake-up satellite peaks at a smaller film depth; the peak intensity is reduced at a higher depth. The relative intensity of Cu and Ti increases at a larger film depth. The optical band gap varies from 1.83 to 2.20 eV at different film depths.

We report the surface stoichiometry of Ti${}_x$-Cu${}_y$N${}_z$ thin film as a function of film depth. Films are deposited by high power impulse (HiPIMS) and DC magnetron sputtering (DCMS). The composition of Ti, Cu, and N in the deposited film is investigated by X-ray photoelectron spectroscopy (XPS). At a larger depth, the relative composition of Cu and Ti in the film is increased compared to the surface. The amount of adventitious carbon which is present on the film surface strongly decreases with film depth. Deposited films also contain a significant amount of oxygen whose origin is not fully clear. Grazing incidence X-ray diffraction (GIXD) shows a Cu${}_3$N phase on the surface, while transmission electron microscopy (TEM) indicates a polycrystalline structure and the presence of a Ti${}_3$CuN phase.

A comprehensive study on the electronic structure and optical properties of a Cu₃N film is performed by the first-principles study using density functional theory. The Hubbard (U) term is added in the local density approximation approach for improvement of the theoretical band gap energy. The band structure of the Cu₃N unit cell shows a strong hybridization of Cu 3d and N 2p orbitals in the near-valence band region (M) because of their antibonding states which are also observed by molecular orbitals (HOMO–LUMO). The conduction band is dominated by a very small amount of Cu 3p and N 2p orbitals. The density of states exhibits a negligible deformation in Cu–N bonding. The Cu₃N thin film deposited by the DC magnetron-sputtering technique shows a polycrystalline structure with a nonstoichiometric Cu₃N phase. The experimentally obtained optical band gap and refractive index of the Cu₃N film are 1.44 eV and 2.14, respectively, which are comparable with those from the theoretical approximation.