Self-Assembling Fabrication And Optical Properties Of SiO₂ Series 3-D Photonic Crystals

Since the conception of photonic crystal was projected, fabrication and research of 3-dimensional photonic crystals have received great attention because of their potential application in optical communication and optical integrated circuit. Different photonic crystal structures were designed such as opal, Yablonovite structure, woodpile structure and slanted pore structure (SPn structure). Meanwhile, lots of fabrication methods were presented, such as self assembly method, ion beam etching, photoelectrochmical etching, laser interferometric lithography and two-photon polymerization. How to precisely control periodic alignment of photonic crystal structure and avoiding appearance of useless defects are very important during the fabrication process.This paper mainly introduces the way of fabrication and disscusion of optical properties of the 3-D photonic crystals. Opal structure photonic crystal and composite photonic crystal have been fabricated by vertical deposition method and electro deposition method. The morphology, components, structure and optical properties of the samples were characterized by different instruments. The important results are listed as follows:1. Optical properties of SiO2 photonic crystals fabricated by vertical deposition using one substrateThe uniform SiO2 particles were synthesized by modified Stober method, and big particles with the diameter of 550nm were synthesized by divided step method. SiO2 photonic crystals in visible range were fabricated by vertical deposition. Optical properties of SiO2 photonic crystals and influence of annealing on the optical reflectance were studied.2. Fabrication and optical properties of SiO2 photonic crystals by vertical deposition in different conditionsThe uniform SiO2 particles with the diameter of 200nm were synthesized. SiO2 photonic crystals were fabricated in different conditions:light irradiation, evaporation rate, insertion mode (single substrate or double substrates). We studied the surface morphologies of the samples fabricated in different conditions, and we found that:the defects in the photonic crystals were greatly reduced under such experiment conditions:slow evaporation rate, dark environment and double substrates parallel insertion mode. We studied the optical properties of the samples prepared under optimal conditions.3. Fabrication and optical properties of SiO2 photonic crystals with controllable thicknessIn the same concentration of SiO2 suspension, SiO2 photonic crystals with different thickness were successfully fabricated by modifying double substrates vertical deposition method. It shows that the thickness of the samples can be easily controlled by adjusting the distance between the two substrates. Meanwhile, some changes have taken place in surface morphology of samples with different thicknesses. At the same time, we studied the optical properties of the samples with different thickness.4. Fabrication and optical properties of SiO2-NiO composite photonic crystals by dip-coating methodUsing SiO2 colloidal crystal film as template, SiO2-NiO composite photonic crystal prepared by modified dip-coating method. The causes of arising defects in the structure and their influence on optical reflective properties have been discussed.5. Fabrication and optical properties of SiO2-ZnO composite photonic crystal prepared by electro deposition and the optical reflective property of the samplesSiO2-ZnO composite photonic crystals were successfully synthesed on the ITO substrates by electrodeposition and calcination. The influence of deposition time on the morphology and optical properties of the SiO2-ZnO composite photonic crystals were investigated.6. SiO2-NiO and SiO2-ZnO composite photonic crystal prepared by coating first methodA new method named coating first method was proposed to fabricate core-shell composite photonic crystal. NiO-SiO2 and SiO2-ZnO composite photonic crystals were prepared by this method, respectively. The surface morphologies were characterized by SEM and compared with those of samples prepared by dip-coating method. It’s found that the defects in the structure are different with those of samples prepared by dip-coating method.7. The fabrication of ZnO colloidal crystal filmsZnO particles were synthesized by two-step method (also named seed solution method) projected by Eric W. Seelig. ZnO colloidal crystal films were prepared by vertical deposition. The diameter and dispersion of ZnO particles synthesized in different experiment conditions were discussed.