Correlation between room temperature luminescence and energy-transfer in Er-Au co-implanted silica

We report on the room temperature photoluminescence characterization in the visible and near-infrared range of Er-Au co-implanted silica systems as a function of the annealing temperature. Besides the characteristic Er3+ emission at 1540 nm, the samples exhibit luminescence bands in the wavelength region 600-1400 nm related to the formation of ultra-small AuN aggregates with a number of atoms N less than 50 atoms. In particular, the correlation between such AuN-related luminescence and the enhancement of the Er3+ emission was investigated and an anti-correlation between the Er3+ luminescence at 1540 nm and an AuN-related band at 980 nm was revealed that represents a possible path for the energy-transfer from AuN nanoclusters to Er3+ ions, giving rise to the Er3+ sensitized emission.