1.5µm light emission of Er³⁺ ions doped in SiO₂ films including Si nanocrystallites and in SiO_x films

We have investigated the fabrication of two types of Er-doped silicon oxide films. The films were prepared by ablating a Si target covered with a thin Er metal layer, by Nd:YAG laser light at 50 mJ/pulse in 40 Torr O₂ gas. After depositing the Er-dispersed SiO_x (x ∼ 1.4) films, the films were annealed in Ar gas. We found that Er-doped films deposited at (a) 4 J/cm² and (b) 100 J/cm² have the optimum annealing temperatures of 600°C and 900°C, respectively. Furthermore, we found that Er-doped films deposited at 4 J/cm² exhibit much more intense light emission at 1.5 µm than those deposited at 100 J/cm². For the Er-doped films deposited at 100 J/cm², it is evident that electron-hole pairs are generated in Si nanocrystallites precipitated in a SiO₂ film and that recombination energy is transfered to Er³⁺ ions that emit 1.5 µm light, via the lowest luminescent state in Si nanocrystallites.