Sensitization of the 1.54 μm luminescence of Er3+ in SiO2 films by Yb and Si-nanocrystals

A systematic study of excitation of the 4f–4f luminescence of Er3+ ions near 1.5 μm in SiO2 layers codoped with Yb and containing Si-nanocrystals (nc-Si) is presented. Layers of SiO2 were implanted with Er+ and Yb+ ions at the energies of 800 and 830 keV, respectively, at a wide range of doses (0.5–4.0×1015 cm−2). Photoluminescence (PL) and PL excitation spectroscopy were applied to study excitation of Er3+ ions. The Yb3+ ions were found to play a key role in sensitizing the PL of Er3+ for pump wavelengths ∼500 nm and 1μm. Models of sensitization processes involving energy transfer from Yb-centers are discussed. Silicon nanocrystals were produced by high dose Si implantation into SiO2 (excess Si contents ∼7%) followed by annealing at 1100°C. An evidence is presented that transfer of energy from nc-Si is not the dominant mechanisms of excitation of Er3+ ions. Defect mediated mechanisms seem to be more efficient. It is also found that excess Si in SiO2 prevents clustering of rare earth atoms.