Sol-gel processing of germanium sulfide based films

Germanium sulfide is transparent in the 0.5-10 mu m wavelength region and the possibility of preparing germanium sulfide glass films by sol-gel processing is of interest for applications such as planar waveguides for integrated optics. We describe possible alternative ways of using sol-gel processing for the liquid phase deposition of germanium sulfide based films. The Ge precursors used were germanium tetrachloride and germanium tetraethoxide, while the different sources of S utilized were thiourea, thioacetamide and hydrogen sulfide. Infrared spectroscopy, ellipsometry, and X-ray photoemission spectrometry measurements were made on the films. Although some oxide contamination was evident in most films prepared, refractive indices close to that expected for dense GeS2 glass were usually obtained. In some cases, the film composition contained germanium sulfide without detectable oxide impurities. (C) 1999 Published by Elsevier Science B.V. All rights reserved.