Preparation and optical studies of Er-doped Al-Si-Ti oxide glasses using the ErAl3(OPr^i)12 isolated Er-ion precursor

Journal article, 2000

We have investigated the possibility of avoiding formation of Er-rich oxide clusters in ErAl3O6–TiO2–SiO2 glassy films. Samples containing 0.5, 1 and 3 mol% Er31 were prepared using a precursor with a single, isolated Er-ion, ErAl3(OPri)12, in the metal–organic sol–gel route. The thermal decomposition of the gel films to form amorphous oxide films was studied by thermogravimetry, Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction and by means of a transmission electron microscope, equipped with an energy dispersive spectrometer. The microscopy studies of the oxide films obtained after 2 h at 9008C showed that they were amorphous and free of Er-rich clusters. The optical and vibrational properties of the glasses were studied using FT-IR, Raman scattering and luminescence spectroscopy. The samples exhibit luminescence both in the visible and IR under excitation of the 514.5 and 488 nm Ar1 laser lines. The emission around 1.5 mm was maximum for the 1 mol% sample. The results show that the preparation technique can produce samples with an unusually large amount of Er doping, before Er-clustering induced quenching of the luminescence appears. Up-converted emission was also detected around 21 000 and 24 500 cm21.