Sm3+ photoluminescence in co-sputtered SiO2 thin films.

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]