Structural investigation of photonic materials at the nanolevel using XPS

This work deals with X-ray photoemitted spectra (XPS) from materials which are of interest for photonic applications. In particular xHfO₂ ? (100 ? x) SiO₂ (x = 10, 20, 30 mol%) glass–ceramics planar waveguides and silver ion-exchanged (0.5, 1.5, 5 mol%) sodalime glasses are investigated. The aim of the work is to explore the material structural changes occurring at the nanometric scale which are produced during the fabrication process in order to enlighten the formation of the nanostructures. The results show that XPS is sufficiently sensitive to detect the formation of nanostructures in the analyzed materials providing at the same time also chemical information. Both these inputs are important to tune the production processes to increase the efficiency of the optical devices.