Impact of the annealing temperature on the optical performances of Er-doped Si-rich Silica systems

Series of Er-doped Si-rich silicon oxide (SRSO:Er) layers were grown by magnetron sputtering at different temperatures from ambient to 500 degrees C and then annealed between 600 degrees C and 1100 degrees C. They were characterized by spectroscopic and time-resolved photoluminescence (PL) measurements. Significant PL was detected at 1533 nm from the as-grown samples at T >= 300 degrees C excited by a non-resonant wavelength (476 nm), hence indicating the formation of Si-based sensitizers during the growth process. The PL intensity and the decay lifetime of Er3+ ions were both greatly increased with the annealing temperature. An optimum temperature of annealing is obtained at 800 degrees C, which is expected to favor the formation of very dense and small sensitizers. The fraction of Er coupled to sensitizers was found nearly 6-7 times higher than that reported so far in the literature.