Design of photonic structures by sol gel-derived silica nanospheres.

Sol–gel processing was used to obtain monosized silica spheres of 270 nm in diameter. Starting from these spheres, two different systems have been fabricated: (i) 3D Photonic Crystals by means of vertical deposition and evaporation-assisted sedimentation deposition methods; (ii) core-shell-like Er3+-activated silica spheres, where the core is the silica sphere and the shell is an Er2O3–SiO2 coating. Optical and spectroscopic assessment, as well as morphological and structural characterization of the systems, have been performed.