Fabrication Of Silica And PS Colloid Crystals And Pilot Study For Synthesis Of Inverse Opal

Photonic crystals are 3D structures with a dielectric constant that varies largely and periodically with lattice spacing comparable to the wavelength of light. This creates a periodically varying scattering potential for the light, giving the material optical properties similar to the electrical properties of a semi-conductors. It has attracted much attention to their capacity for manipulating, confining, and controlling light for many potential applications in photonics and electronics fields.For the past decade, a lot of interest has been focused on the formation of 1D and 2D assemblies. A promising technique to fabricate 3D photonic crystals with a photonic band gap in the optical wavelengths is the self-assembling growth of spherical colloid particles. For example, monodispersed PS or SiO₂ particles could be assembly into colloid crystals. However, these structures do not have perfectly photonic properties because of their low refractive index. Photonic behavior can be enhanced by infiltrated the voids of opals with higher refractive index materials. In this method, the preparation of micro-spheres with uniform size and high stability and synthesis of colloid crystal templates are the most important technical problems. So, on the basis of the conclusions drawn by predecessors, the preparation of polystyrene and silicon colloid particles and the templates assembly with them and fill CdS into the holes of templates have been studied in this paper. In this paper, we did the following research work.PS colloid particles were prepared by soap-free emulsion polymerization and SiO₂ colloid particles were prepared by Sto|¨ber process. The effects of the reaction conditions are discussed simply. PS colloidal crystals were synthesized with centrifugal sediment technique and vertical deposition technique. SiO₂ colloidal crystals were synthesized with gravity sediment technique and vertical deposition technique. The quality of the colloidal crystals was tested by SEM and transmission spectrum. Then the colloidal crystals were used as templates. CdS were filled into the holes and the quality of the samples was discussed by SEM and AFM.