[en] In this thesis project we present the results on the generation of laser-induced periodic surface structures (LIPSS) in thin bismuth films. The films were deposited by the pulsed laser ablation technique on glass substrates, using two wavelengths: 1064 nm and 532 nm. Polycrystalline bismuth films were obtained with preferential orientation in the direction (003), a characteristic that depends on the plasma parameters. The deposits were morphologically and structurally characterized by profilometry, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and micro Raman spectroscopy. Subsequently, the films were irradiated in punctual areas with the same laser used for ablation and both wavelengths. The fluence and pulses number were determined and those were kept constant in all the experiments. The irradiated areas were characterized by atomic force microscopy and micro Raman spectroscopy. The results show the periodic structuring on surface of bismuth films in the irradiated areas. A difference is observed in the LIPSS recorded on the polycrystalline films with respect to the oriented films. The grooves are much more parallel in the textured films, unlike the LIPSS in polycrystalline films that are seen in a corrugated form. There is also a difference in the width and height of the grooves. Finally, it was determined that there is a limit on the thickness of the films from which it is possible to generate LIPSS. (Author)

[en] Photo catalysis is a method widely used in the degradation of organic pollutants of the environment. The development of new materials is very important to improve the photo catalytic properties and to find new applications for TiO₂ as a photo catalyst. In this article we reported the synthesis of a photo catalyst based on TiO₂ doped with Zn²⁺ ions highly efficient in the degradation of nitrobenzene. The results of photo catalytic activity experiments showed that the Zn²⁺ doped TiO₂ is more active that un-doped TiO₂ catalyst with an efficiency of 99% for the nitrobenzene degradation at 120 min with an apparent rate constant of 35 x 10^-3 min^-1. For the characterization of photo catalyst X-ray diffraction, transmission electron microscopy and Raman spectroscopy were used. (Author)