Er3+ environment in TeO2-ZnO-Na2O glasses

70TeO(2)-20ZnO-10Na(2)O glasses can be doped by up to some percents in Er3+, and the doped glasses have a luminescence line around 1.55 mum, broader than 70 nm, making them suitable potential materials for multiplexer devices. As the shape and intensity of the luminescence line is determined by the local site around Er3+, X-ray absorption spectroscopy was used here to determine this local environment in a series of glasses doped with 1-5 wt% Er2O3. Measurements made in the usual conditions of data range give results similar to those obtained in the literature for other multicomponent oxide glasses. The fitting procedure gives an average coordination shell of around 7 oxygen atoms at a distance of around 0.23 nm. The disorder in this shell is expressed by a Debye Waller term, relatively small (<0.01 Angstrom(2)) in view of the broadness of the luminescence emission line. Complementary measurements were performed in the transmission mode on the most concentrated samples over a larger k-extension. Based on the qualitative analysis we suggest the existence of an additional site, with larger distances to the oxygen neighbors. This additional site could be responsible for the broadening of the luminescence lines. (C) 2002 Elsevier Science B.V. All rights reserved.