کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1497652 | 1510801 | 2006 | 4 صفحه PDF | دانلود رایگان |
Er3+-doped silica waveguides, co-doped with aluminium, titanium, and hafnium oxides, were prepared using the sol–gel method and dip-coating processing. Here, we present a characterisation of the local environment around Er3+ ions, as determined from the Er L3-edge extended X-ray absorption fine structure (EXAFS) measurements performed at ESRF (France). The first coordination shell is composed of 5–6 oxygen atoms at distances ∼2.32–2.35 Å, slightly varying as a function of the modifier oxide. Er3+ nearest neighbors distance does not show a significant compositional dependence. On the contrary, outer shells analysis shows significant differences: Al2O3 doping (less than 2% mol) induces an ordering around Er and increases the distance of the second shell, probably due to the substitution of Si by Al atoms; for TiO2 doping (7–15% mol), it is most probable that the second shell is composed from Si atoms as the case of pure SiO2; for HfO2 doping (from 10 to 50 mol%) there is a very clear evidence of Er–Hf coordination already at the lowest Hf content, but still in amorphous environment.
Journal: Optical Materials - Volume 28, Issues 6–7, May 2006, Pages 864–867