Lanthanide-doped silica layers via the sol-gel process: luminescence and process parameters

The introduction of luminescent materials into a sol-gel-derived silica layer is a promising way for the creation of optical applications on the basis of UV-sensitive waveguides. In this work, the preparation of tetraethylorthosilicate (TEOS)-derived silica layers doped with terbiumtrisbenzoate is described. Results with respect to the layer thickness, the photoluminescence of doped bulk silica materials compared to doped silica layers, the influence of ultrasonic treatment during preparation, and the temperature stability are given. Atomic force microscopy measurements show that the withdrawal speed during the sol-gel process can be optimized in order to minimize the surface roughness of the films deposited. Nanoindentation experiments reveal that the hardness of layers cured at 200 degreesC is comparable to that of ordinary glass. (C) 2004 Elsevier B.V. All rights reserved.