Effect of aluminum co-doping on fluorescence properties of Sm2+-doped SiO2 films prepared by rf magnetron sputtering method

Thin films of aluminum co-doped SiO2: Sm2+ were prepared by rf magnetron sputtering method. Effects of Al dopant on fluorescence spectra and local structure of Sm2+ ions were studied. The peak intensity due to the D-5(0)-F-7(0) transition of Sm2+ ions increases by more than one order of magnitude with an addition of Al dopant. For specimens with low concentration of Sm2+, the peak intensity increases with an increase in the Sm2+ concentration. The rate of the increase in peak intensity with Sm2+ concentration depends on the kind of co-sputtered Al compounds. The width of the peak becomes narrow, and the position of the peak shifts to a shorter wavelength with an addition of Al dopant. It is thought that the addition of Al dopant prevents the clustering of Sm2+ ions and leads to the homogeneous dispersion of Sm2+ ions in the SiO2 glass matrix.