Towards an enhanced coupling between the Er ions and Si nanoclusters

The reactive magnetron co-sputtering of two confocal SiO2 and Er2O3 cathodes in argon-hydrogen plasma was used to deposit Er-doped Si-rich-SiO2 layers. The effects of deposition conditions (such as hydrogen rate and substrate temperature) and annealing treatment (temperature and time) on the structural, compositional and photoluminescence (PL) properties of the layers were examined. An enhancement was observed of both Er3+ PL emission and Er3+ lifetime at 1.54 mu m in comparison with their counterparts for the best samples reported so far. It was shown that a lifetime as high as 9 ms can be reached, with comparable PL intensities for resonant and non-resonant excitation lines. The effective cross-section and the fraction of Er ions coupled to Si clusters are analyzed. (C) 2008 Elsevier B.V. All rights reserved.