Simulation Of Photonic Band And Study On Preparation For Nesting Complex-period Photonic Crystal Structure

Photonic crystal caused extensive concern in numerous field such as physics and material science because of their unique properties in terms of light propagation. As photonic crystal has been used more and more recently, only producing photonic bands would not satisfy more complex applied needs and it is more critical to modulate the bands accurately. So complex structure and compound material has became research main current. For studying the method to modulate the photonic bands accurately, in this thesis a new structure, nesting complex-period photonic crystal structure, was established. Comparing to simple photonic crystal structure, there are more parameters can modulate bands in nesting complex-period structure.This thesis aimed to comprehend the new optical properties of the new complex-period structure in theory, to find out appropriate preparation method and to fabricate the stuctures successfully. These would lay substantial technique foundation for the subsequent experiment study on optical function and the promotion in new devices. The main contents are as follows:1. The photonic bands of new 2D nesting complex-period structures were theoretically investigated. The influence of fill ratio of outside period, fill ratio of inside period, shape of outside period units and material on photonic bands were investigated. Calculation revealed that the range of band were mostly adjusted by outside-period structure, and inside-period structure dominated the bands both by changing fill ratio and by the period effect of inside-period structure, the latter contributes to bands in TM mold but obstructs bands in TE mold. These properties validated the feasibility that the band were modulated by much little period structure in nesting complex structure.The photonic bands of 2D/3D and pseudo 3D nesting complex-period structures were theoretically investigated. As 2D nesting complex-period structures, Calculation revealed that Outside and inside period structure affected the bands together, which is the most unique properties of nesting complex-period structures.2. For fabricating 2D nesting complex-period structure, a new method, "anodization in defined region" was introduced for the first time, which combined electrochemical oxidation with capillary force lithography technology. The technics for preparation of outside and inside period structure as well as compatibility of them were studied. (1) r, d and r/d were affected by anodic voltage or temperature, more higer was anodic voltage or temperature, r or d was more larger, but r/d would keep steady after anodic voltage or temperature increased to high enough. On the other hand, r would increase alone by overtime enlarging, which would cause the r/d increase at the same time. In addition, the order of pores array could be improved through annealed, anodic polished, or increasing anodic time. (2) Lacunas due to styrene vaporizing during polymerization would weaken the protection of polystyrene film. The vaporize was the fewest when the concentration of solicitation was 0.5%, in addition, raising temperature and decelerating rotate also could improve the protection of polystyrene film. Ultimately, the film obtained by using best technics would protect the substrate from electrolyte for 48 hours. (3) Experiments showed capillary force lithography could cooperate well with electrochemical oxidation technology, and finally 2D nesting complex-period structure was fabricated successfully. (4) Following the confinement of electrochemical oxidation and capillary force lithography technology themselves, The size of 2D nesting complex-period structure could be prepared with "anodization in defined region" was estimated.3. For fabricating 2D/3D nesting complex-period structure, a new method, "convective assembling in defined region", was put forward, and in a creative way, PECVD was used to fill the voids of prepared silica colloidal crystals in Si flute with Si. After outside period structure (flutes array in si wafer) had prepared with micro fabrication technology, the technics for fabrication of inside period structure, Si inverse opal structure embedded in Si flutes, were studied. (1) The influences of gradient, sphere concentration, temperature and cubage on assembling quality of SiO₂ colloidal spheres are systematically studied. As gradient, temperature, or sphere concentration increased, the assembling quality was improved first then got worsen. In addition, the assembling quality got worsen as cubage was enlarged. The best preparation procedure was found out that could both satisfy the request of 2D/3D nesting complex-period structure, assembling quality should higher than 12.5%, and could cost the least time. (2) The influences of technics in PECVD procedure were studied. The results indicate: rf power, flow rate or pressure in reaction chamber could control the concentration of SiH₂. And temperature could affect the reaction rate, the concentration and the diffuseness of SiH₂. Reducing the concentration of SiH₂ or raising the temperature could contribute to sediment evenly. As the channels for transfer not being plugged up, compact inverse opal could be obtained with prolonging sediment time. And the orderly opal structure is also important in this method. Finally, 2D/3D nesting complex-period structure was fabricated successfully after 14 hours' deposition with deposition rate under 200nm/h.4. In this thesis, the mechanism during the growth of colloidal crystals in confined space of flutes array was probed. The result of simulation accorded well with the experiments. And according this mechanism, The size of 2D/3D nesting complex-period structure, could be prepared with "convective assembling in defined region", was estimated.5. Base on technics for fabrication of 2D/3D nesting complex-period structure, after discontinuous deposition was used to substitute the single deposition process and polishing was added, two lays of 2D/3D nesting complex-period structure were fabricated, which verified it was doable to fabricat pseudo 3D nesting complex-period structure with this method.6. According the stimulated optic properties that 2D nesting complex-period had more modulation on polarization mold and nesting complex-period structure could produce super narrow photonic band, the latent applications in camouflage for recognition with polarization information and laser protection for detection systems were introduced.