| Photonic crystals have the special feature of modulating the propagation of lightwave, are one of the basis of photonic communication technology and photonic computer and also the frontier of functional materials. Presently, the fabrication of photonic crystals, especially those using for visible or near-infrared region, is the key to the development of photonic crystals. In this thesis, SiO2 colloidal spheres were prepared by the base-catalyzed method and self-assembled into photonic crystals films of visible or near-infrared region by the vertical deposition method. The main contents and results are as follows:First, SiO2 colloidal spheres were synthesized by the base-catalyzed method. Influence of the composition ratios of the reactants on the SiO2 particle size and size deviation was mainly investigated.Second, silica gel microspheres with different diameter and concentrations were self-assembled into a variety of photonic crystal films through the vertical deposition method, their microstructure and optical properties are characterized by scanning electron microscopy and UV-visible-near infrared spectrophotometer. The results showed that: (1) The films were three-dimensionally ordered crystal structure, there were obvious point and line defects on the surface, and the line defects decreased as the decreasing of the size of microspheres. (2) We found that the silica spheres being dehydrated at a suitable temperature first, the defects of the films significantly reduced. (3)Self-assembly photonic crystal films showed photonic band gap whose position depended on the diameter and structure of microspheres, and the central wavelength of the band-gap is agreement with the theoretical value which results from Bragg Reflection Law. (4) The depth of photonic band gap increased as increasing concentration of microspheres, which mean better photonic band gap properties, but when the concentration is more than 10%, the depth of the band gap will be reduced. |
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