Electronic and optical properties of Ta 1 − x Zr x N films: Experimental and ab initio studies

This article reports on a systematic investigation of the electronic and optical properties of Ta 1 − x Zr x N films fabricated using unbalanced magnetron sputtering. X-ray diffraction confirmed that the films formed a solid solution that corresponded to a rocksalt structure. Rutherford backscattering revealed the elemental composition of the films. Ultraviolet photoelectron spectroscopy was used to investigate the valence band electronic structure while vacuum ultraviolet spectroscopic ellipsometry (VUV–SE) was used to evaluate the strength and energy of their interband electronic excitations/transitions. The optical and electronic properties of these materials were simulated using density functional theory within the generalized gradient approximation. The calculated refractive indices and density of states were in good agreement with the VUV–SE data and the valence band photoelectron spectra. In addition, the computational results were instrumental in indicating the correlation between the measured optical and electronic properties to their bond strength and elemental composition.