Sol-gel derived Ce3+-doped aluminosilicate planar waveguides: a study by X-ray photoelectron spectroscopy

Sol-gel derived aluminosilicate planar waveguides doped with cerium ions ha ve been produced using the dip-coating technique. Optical characterisation of the waveguides has been performed by m-lines technique. Waveguide Raman Spectroscopy showed that while crystallisation occurs at 1000 degrees C, he at treatment at 900 degrees C yields films which are totally amorphous. X-r ay photoelectron spectra clearly indicate that cerium is present as Ce3+ io ns. Moreover, surface atomic ratios determined by XPS demonstrated that the measured concentrations of cerium ions are proportional to the targeted on es, even if slightly lower. Finally, depth profiles demonstrated that the f ilms are homogeneous on a wide scale and that cerium could have a catalytic effect on the elimination of carbon impurities on the outer surface of the samples. (C) 1999 Elsevier Science B.V. All rights reserved.