基于表面微结构的太赫兹吸收层研究

发布时间：2019-04-23 08:17

【摘要】：太赫兹(Terahertz,THz)波是指频率在0.1-10THz范围内的电磁波,介于毫米波与红外波之间。与其它波段的电磁辐射相比具有瞬态性、宽带性、低能性、穿透性、惧水性等独特性质。太赫兹探测器是太赫兹科学技术应用的关键器件之一,太赫兹波吸收材料及吸收结构是高性能太赫兹探测器的重要保障。本论文针对太赫兹吸收展开超材料结构及多孔粗糙材料的设计与制备研究。超材料结构被证实可以高效吸收设定频段太赫兹波辐射,但该结构与基于微测辐射热计的探测单元兼容性差,本论文设计了基于微桥结构的超材料图形并进行了分析优化。本文先设计尺寸为56μm×56μm十字架超材料结构,CST仿真软件模拟结果表明,该结构在2.52THz处对太赫兹波的吸收率近100%;通过该超材料结构的电场、表面电流、功率流、功率损耗等的信息分布可以看出吸收的太赫兹波辐射电场主要分布在顶层结构上,吸收频率主要由顶层结构决定,入射太赫兹辐射的功率损耗主要分布在介质层。本文还设计了不同尺寸和厚度的超材料结构,通过CST仿真确定了超材料结构对太赫兹辐射吸收的关系。为了将超材料图形与微桥结构兼容需缩小超材料图形尺寸,本文设计了一种顶端扩展的十字架结构,尺寸单元为28μm×28μm,仿真模拟表明该结构对相同频率的太赫兹波也能实现将近100%的吸收。同时,对设计的结构进行了实际制备,测试结果表明,对太赫兹辐射有明显的吸收峰。本文还设计新颖的锯齿状微型天线对结构,与一般的天线相比具有尺寸小的特点,该结构在2.75THz处对太赫兹波的吸收率接近1。制备完成的天线结构测试表明对太赫兹辐射有明显的吸收峰。在多孔粗糙表面吸收方面,本文设计并用直流电化学腐蚀法制备了单层多孔硅结构。通过优化实验参数确定了直流电流参数为0.125A,腐蚀时间为20-30min,可以制备效果较好的单层多孔硅。在单层多孔硅表面镀上厚度20nm的NiCr金属薄膜,这种复合结构作为太赫兹辐射吸收层,通过测试发现多孔硅与NiCr薄膜相结合的吸收层对太赫兹辐射的吸收率最高能达到33.5%。
[Abstract]:Terahertz (Terahertz,THz) wave is a kind of electromagnetic wave with frequency in the range of 0.1-10THz, which is between millimeter wave and infrared wave. Compared with the electromagnetic radiation of other wavebands, the electromagnetic radiation has the characteristics of transient, broad band, low energy, penetrating and water-repellent. Terahertz detector is one of the key devices in the application of terahertz science and technology. The terahertz wave absorbing material and structure are the important guarantee for the high performance terahertz detector. In this paper, the structure of terahertz absorption supermaterial and the design and preparation of porous rough material are studied. The supermaterial structure has been proved to absorb terahertz radiation in the set frequency band efficiently, but this structure is not compatible with the detection unit based on the micrometer radiometer. In this paper, the supermaterial graphics based on the microbridge structure are designed and analyzed and optimized. In this paper, the size of 56 渭 m 脳 56 渭 m cross superstructure is first designed. The simulation results of CST software show that the absorption of terahertz wave at 2.52THz is nearly 100%. Through the information distribution of electric field, surface current and power loss of the supermaterial structure, it can be seen that the absorbed terahertz wave radiation electric field is mainly distributed on the top structure, and the absorption frequency is mainly determined by the top structure. The power loss of the incident terahertz radiation is mainly distributed in the dielectric layer. The superstructure with different size and thickness is also designed in this paper. The relationship between the terahertz radiation absorption of the supermaterial structure and the terahertz radiation absorption is determined by CST simulation. In order to make the metamaterial graphics compatible with the micro-bridge structures, we need to reduce the size of the metamaterial graphics. In this paper, we design a kind of cross structure with an extended top. The size unit is 28 渭 m 脳 28 渭 m. Simulation results show that the structure can also achieve nearly 100% absorption of terahertz waves at the same frequency. At the same time, the experimental results show that the terahertz radiation has an obvious absorption peak. In this paper, a novel sawtooth micro antenna pair structure is designed. Compared with the common antenna, the structure has the characteristics of small size. The absorption rate of terahertz wave at 2.75THz is close to 1. The structure test of the prepared antenna shows that there is an obvious absorption peak for terahertz radiation. In the aspect of porous rough surface absorption, the monolayer porous silicon structure was fabricated by DC electrochemical etching method. By optimizing the experimental parameters, the DC current parameter is 0.125A, the corrosion time is 20 min, and the monolayer porous silicon can be prepared. NiCr metal thin film with thickness of 20nm was deposited on the surface of single layer porous silicon. The composite structure was used as terahertz radiation absorbing layer. It was found that the absorption rate of terahertz radiation was up to 33.5% by the absorption layer combined with porous silicon and NiCr film.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O441.4

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