Evidence of energy coupling between Si nanocrystals and Er3+ in ion-implanted silica thin films

Silica thin films containing Si nanocrystals and Er3+ were prepared by ion implantation. Excess Si concentrations ranged from 5% to 15%; Er3+ concentration for all samples was 0.5%. Samples exhibited photoluminescence at 742 nm (attributed to Si nanocrystals), 654 nm (defects due to Er3+ implantation), and at 1.53 μm (intra-4f transitions). Photoluminescence intensity at 1.53 μm increased ten times by incorporating Si nanocrystals. Strong, broad photoluminescence at 1.53 μm was observed for λPump away from Er3+ absorption peaks, implying energy transfer from Si nanocrystals. Erbium fluorescence lifetime decreased from 4 ms to 1 ms when excess Si increased from 5% to 15%, suggesting that at high Si content Er3+ ions are primarily situated inside Si nanocrystals.