ERBIUM DOPED SiO2-TiO2 OR SiO2-TiO2-Al2O3 NANOPOWDERS PREPARED BY SOL-GEL METHOD

The Er3+ doped silica-titania or silica-titania-alumina nanopowders were prepared by sol-gel method that represents one of the most flexible and convenient way to prepare oxide films and nanopowders. The selected molar compositions were un-doped and 0.5% Er2O3 doped 90% SiO2-10% TiO2 and 85% SiO2-10% TiO2-5% Al2O3 systems. Similar compositions were previously used for obtaining films for waveguides applications but the mechanism of the phase formation by thermal treatment of the corresponding gels was not previously approached. The gels obtained by gelation of the solutions were analyzed by thermogravimetric and thermodifferential analysis (DTA/TGA) in order to determine their thermal behavior and by IR spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) to evaluate their structure and morphology. Based on the results obtained, the gels were thermally treated at 500 degrees C and 900 degrees C. The thermally treated powders were characterized by SEM, FT-IR, X-ray diffraction (XRD) and photoluminescence (PL). The significant influence of the Er3+ on the phase formation was established in both studied systems.