Photonic bandgap dieletric structures fabricated by sol-gel and rf-sputtering techniques

A protocol to synthesize silica spheres by sol-gel route, which permits the controlled growth of spherical particles of uniform size, for the fabrication of good quality opal is described. Two different methods, vertical and evaporation-assisted sedimentation deposition method, are used for the preparation of close packed arrangements of the spheres. The structure of the samples was investigated by scanning electron microscope. Moreover we have investigated the optical properties of opals by optical reflection and transmission measurements. The results indicate that the deposited structures are compatible with a three dimensional face centered cubic order in these solids structures.