RESUMEN
Eu3+-doped oxide thin films possess a great potential for several emerging applications in optics, optoelectronics, and sensors. The applications demand maximizing Eu3+ photoluminescence response. Eu-doped ZnO, TiO2, and Lu2O3 thin films were deposited by Pulsed Laser Deposition (PLD). Pulsed UV Laser Annealing (PLA) was utilized to modify the properties of the films. In situ monitoring of the evolution of optical properties (photoluminescence and transmittance) at PLA was realized to optimize efficiently PLA conditions. The changes in optical properties were related to structural, microstructural, and surface properties characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The substantial increase of Eu3+ emission was observed for all annealed materials. PLA induces crystallization of TiO2 and Lu2O3 amorphous matrix, while in the case of already nanocrystalline ZnO, rather surface smoothening0related grains' coalescence was observed.
RESUMEN
Chromium-enriched diamond-like carbon (DLC) layers were prepared by a hybrid technology using a combination of pulsed laser deposition (PLD) and magnetron sputtering. XRD revealed no chromium peaks, indicating that the layers are mostly amorphous. Carbon (sp(2) and sp(3) bonds) and chromium bonds were determined by XPS from C 1s, O 1s, and Cr 2p photoelectron peaks. Depending on the deposition conditions, the concentration of Cr in DLC layers moved from zero to 10 at.% for as-received sample surfaces, and to about 31 at.% after mild sputter-cleaning by argon ion cluster beam. It should be noted that the most stable Cr(3+) bonding state is in Cr2O3 and Cr(OH)3, and that there is the toxic Cr(6+) state in CrO3. The surface content of hexavalent chromium in the Cr 2p3/2 spectra is rather low, but discernible. The population density of Saos-2 cells was the highest in samples containing higher concentrations of chromium 7.7 and 10 at.%. This means that higher concentrations of chromium supported the cell adhesion and proliferation. In addition, as revealed by a LIVE/DEAD viability/cytotoxicity kit, the cells on all Cr-containing samples maintained high viability (96 to 99%) on days 1 and 3 after seeding. However, this seemingly positive cell behavior could be associated with the risk of dedifferentiation and oncogenic transformation of cells.