【作者】 韩喻；

【导师】 谢凯；

【作者基本信息】 国防科学技术大学 ， 材料科学与工程， 2007， 博士

【摘要】 光子晶体因其能够调控光子传播,在物理、材料等众多领域引起了广泛关注。随着近年光子晶体应用领域的拓展和研究的深入,仅仅产生光子禁带实现光子晶体效应已无法满足应用的需求,对各种器件调制光子禁带的功能提出了更高的要求,复合结构、复杂介质已日渐成为研究主流。为实现光子禁带特性的精确调制,本文以光子晶体周期结构作为突破点,引入更多能够控制禁带特性的结构参数,提出了一种全新的光子晶体结构——嵌套复式周期光子晶体结构。本文以探讨这种全新嵌套复式周期结构的理论禁带特性,探索针对不同维度嵌套复式周期结构的制备方法体系,实现不同维度嵌套复式周期结构的制备为研究目标。旨在为今后以明确的应用需求为牵引,进一步开展嵌套复式周期结构光学性能实验研究和相关器件开发奠定充实的技术基础。研究内容与结论包括:1、针对提出的全新嵌套复式周期结构,在成功建立纯二维嵌套复式周期结构计算模型的基础上,分别研究了介质较连续分布结构类型及高介电常数介质孤立分布结构类型的带隙特性受内、外周期填充率,外周期单元形状,材料介电常数等因素影响的规律。通过与简单周期结构带隙特性的比较,可归纳纯二维嵌套复式周期结构的带隙特点及产生机理:外周期结构参数是光子带隙位置及带隙宽度的主要决定因素,可实现小尺寸调制大波长;内周期结构对带隙特性的微调作用分为两部分:内周期细微结构的引入减小了介质的填充率,改变了有效介电常数,同时内周期的周期效应有助于形成TM模的带隙,而阻碍TE模带隙的形成。与此同时,通过建立二维三维混杂和准三维嵌套复式周期结构模型,获得了与纯二维嵌套复式周期结构相似的,内外结构周期效应同时发挥带隙调制作用的模拟结果。这也成为不同维度嵌套复式周期结构共同具有的最为独特的性质,而较简单周期更易获得超窄禁带成为嵌套复式周期结构另一个显著特性。2、制备了氧化铝材料体系纯二维嵌套复式周期结构。在制备工艺中,开拓性地将毛细微模塑技术和电化学阳极氧化技术结合,提出了一套全新的毛细微模塑图案化限域铝阳极氧化方法。通过对r/d可控的铝阳极氧化方法、毛细微模塑限域工艺及其两者兼融性地研究,掌握了相关工艺参数对纯二维嵌套复式周期结构制备的影响规律,并最后成功实现了氧化铝材料体系纯二维嵌套复式周期结构的制备。（1）在成孔范围内,r、d和r/d受阳极氧化电压及体系温度影响;通过后期扩孔单独增大r,也可以提高r/d;可借助热处理及电化学抛光等预处理过程和增加阳极氧化时间改善孔阵列的有序性。（2）苯乙烯聚合过程中单体挥发产生的空隙是影响涂层隔绝电解液性能的关键因素之一,而引发剂浓度、聚合温度和旋转涂敷速度都将对其产生影响。引发剂浓度0.5%时单体挥发最少,提高聚合温度和减慢旋转涂敷速度也有助于提高聚苯乙烯涂层隔绝电解液的性能。采用最佳制备工艺制得的聚苯乙烯涂层可对阳极氧化过程保证48小时的限域作用。（3）实验证明r/d可控的铝阳极氧化方法和毛细微模塑限域工艺兼容性良好,已成功制备出氧化铝材料体系的纯二维嵌套复式周期结构。同时确定了采用毛细微模塑图案化限域铝阳极氧化方法能够制备的纯二维嵌套复式周期结构内外周期参数范围。3、制备了硅材料体系二维三维混杂嵌套复式周期结构。在制备工艺中提出了微米凹槽内微球自组装技术——“局域对流自组装胶体模板法”,并将原本用于薄膜制备的PECVD技术用于凹槽内微球间纳米间隙的填充。在半导体硅光刻技术制备外周期的基础上,开展了硅凹槽阵列中硅反opal内三维周期结构的制备研究,掌握了二维三维混杂嵌套复式周期结构制备的关键技术,并最后成功实现了硅材料体系二维三维混杂嵌套复式周期结构的制备。（1）探讨了胶体微球浓度、插片角度、环境温度等工艺条件对外周期硅凹槽阵列内胶体微球自组装效果的影响,结果显示:被微球完全排列满的凹槽比例分别随角度、温度和浓度的增大,呈现先增大再减小的趋势,同时自组装效果随环境空间的增大而恶化。综合各影响因素确定了可以满足二维三维混杂嵌套复式周期结构制备要求的最佳工艺条件。（2）对PECVD方法中影响opal结构内外沉积均匀性的影响因素进行了分析,并通过系统实验研究了工艺参数的影响:SiH₂浓度较小时opal结构内外沉积均匀性较好,而调节射频功率、反应室压力和气体流量是SiH₂浓度的有效控制手段。温度将同时影响SiH₂的分解反应速率、SiH₂浓度和SiH₂扩散系数,实验证明升高温度可提高opal结构内外沉积的均匀性。另外,扩散通道不被堵塞的前提下,沉积时间越长,opal结构排列越规整,则整体填充越致密,越有利于反opal结构的形成。选择表层沉积速率低于200nm/h并兼顾温度对结构内外沉积均匀性影响的工艺组合,在沉积14小时并反洗后成功实现了二维三维混杂嵌套复式周期结构的制备。4、针对局域对流自组装这种全新的制备方法,首次建立了动力学过程模型。经过半定量计算,该模型与实验结果吻合较好,可基本正确地描述局域对流自组装过程。同时根据模型确定了采用该方法所能制备的二维三维混杂嵌套复式周期结构内外周期参数范围。5、通过变速PECVD和层间抛光工艺,对二维三维混杂嵌套复式周期结构的制备技术进行改进,基本实现了二维三维混杂嵌套复式周期结构的叠加,验证了该技术路线制备准三维嵌套复式周期结构的可行性。6、根据纯二维嵌套复式周期结构较简单周期具有更强偏振模式调制能力的特点以及嵌套复式周期结构的超窄带特性,提出了将这种新型嵌套复式周期结构应用于偏振伪装和激光防护领域的设想。更多还原

【Abstract】 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.更多还原