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The sensitization of the infrared luminescence of Er ions by Si clusters is studied in oxide films derived from tetraethoxysilane and triethoxysilane gels, doped chemically or by ion implantation with Er and/or Si. No quenching of the luminescence by impurities and structural defects is observed with respect to ion-implanted silica, and a maximum enhancement is observed in the SiO1.5 suboxide formed from triethoxysilane. The segregation of erbium silicide or oxide, depending on the synthesis procedure, deactivates the Er ions when their concentration exceeds 1 at % or the temperature of annealing is above 1050 °C. [ABSTRACT FROM AUTHOR]

Thin films of SiO2 containing Sm were deposited by magnetron co-sputtering. The concentration of Sm in the films was varied by changing the amount of Sm placed on the fused silica target. The samarium content in the films was established by Rutherford back-scattering measurements. Photoluminescence (PL) was excited with the 488-nm line of an Ar ion laser. It consists of several lines in the visible, which are assigned to transitions between multiplets of Sm3+. The concentration dependence of the PL intensity was studied. It passes through a maximum and decreases at higher Sm content. The films were annealed in vacuum at temperatures between 300 and 1000 °C. There was a strong increase in the PL intensity after annealing at 600 °C, and then it fell again after annealing at 1000 °C. The data are compared to spectra of Sm3+ in other matrices. The mechanisms of PL excitation and quenching are discussed. [ABSTRACT FROM AUTHOR]

Ag nanocrystals in a SiO2 matrix were formed by magnetron co-sputtering followed by ion irradiation. The SiO2 : Ag thin films exhibited an absorption resonance in the visible region, due to plasmon polarization of the small Ag crystals. In the as-deposited films, the size of the silver nanoclusters was less than 0.5 nm. After irradiation with 4.5-MeV Au+ ions, the intensity of the absorption peak increased and the peak became narrower, indicating that the crystals had grown. To estimate the average radius, 〈R〉, of the clusters, a computer program based on the Mie theory was used. It was found that 〈R〉 increases linearly as a function of the Au+ ion fluence The method of the disappearing diffraction pattern was used for determining the real part of the refractive index. This index was enhanced with increasing irradiation fluence, probably because the films became more compact. [ABSTRACT FROM AUTHOR]