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Recently there was a considerable interest in the study of various transitional oxy-nitride thin films, due to their remarcable optical and electronic properties, mechanical behaviors and chemical stability. Of this large class, TiNxOy thin films have gained much attention because they offer a variety of applications in many fields. For example, oxygen-rich films have been used as insulating layers in metal-insulator-metal (MIM) capacitive structures in order to avoid oxide interface layer formation, while nitrogen-rich TiNxOy films have been utilized as excellent diffusion barriers. Also, the titanium nitride films containing oxygen are considered to be used as thin films for the resistors. Many other useful applications of TiNxOy films, such as solar selective absorbers, transparent IR window electrodes and wear-resistant coatings have been demonstrated. Another important application is determined by the decorative properties of these coatings.
In this work, we carried out the deposition of TiNxOy and ZrNxOy thin films using reactive pulse magnetron sputtering, on Si and Cu substrates, at different N/O ratios of the reactive gases. The films deposited at room temperature were amorphous, while after samples annealing in air at 850 K, crystalline phases were evidenced.
The aim of this work was to compare the properties of the Ti and Zr based oxy-nitride films in terms of their optical properties, to be used as solar selective absorbers.
The films structure, composition and morphology were studied by using XRD, XPS and AFM. The films microharhness and adhesion on the Cu substrates were dtermined by Vickers intenders and by scratch tests. The colour, the reflectivity and absorbance spectra in UV-VIS-IR region are discussed in terms of N/O ratios, as the colours of these coatings are closely related with their composition, caused by the modification of the electronic structure due to oxygen content.
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