Energy sensitization in erbium-doped silicon-rich oxide films annealed at low temperatures

Si-rich SiO₂ films (SRO) and Er-doped, Si-rich SiO₂ films (EnSRO) were deposited by reactive RF magnetron co-sputtering followed by thermal annealing in a nitrogen atmosphere in order to investigate the optimum condition for efficient 1.54 μm emission. Reference Er in stoichiometric SiO₂ (Er:SiO₂) films were deposited for comparison. The room temperature photoluminescence intensity of SRO films without Er was found to be maximized at 38 at% Si after annealing at 1100°C for 1 hour. On the contrary, we found that the maximized Er photoluminescence of Er:SRO with 38 at% Si and an Er concentration of 10²⁰ cm^-3 occurred for annealing temperatures between 600°C and 800°C. Under these conditions the 1.54 μm Er emission is enhanced by more than two orders of magnitude relative to Er:SiO₂ samples while negligible SRO emission is observed.