表面功能性微纳复合结构的飞秒激光加工

发布时间：2017-12-28 01:29

本文关键词：表面功能性微纳复合结构的飞秒激光加工　出处：《北京理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：自然界在亿万年进化演变中形成了很多奇趣现象,壁虎能飞檐走壁、色彩斑斓的蝴蝶翅膀和荷花出淤泥而不染等现象引发了科研人员的深入研究。分析发现这些特殊现象与生物组织表面结构相关,由规则且有序的微纳米结构组成,正是这些微纳结构改变了材料的力学、光学和疏水性等性能。因此,寻求高效实用的微纳复合型功能性表面结构的制备技术将具有重大意义。近年来随着超快激光技术的快速发展,飞秒激光在功能性表面微纳结构制造方向崭露头角。飞秒激光加工具备精度高、裂纹少、热影响区小的特点,使制备规则有序的微纳结构表面成为可能。因为飞秒激光的脉宽要小于电子-晶格的弛豫时间,在先前于晶格变化时材料已完成对激光能量的吸收过程,此时电子与晶格处于非平衡态,正是这种非平衡、非线性效应,为实现微纳加工奠定基础。本论文在前人飞秒激光加工理论和实验研究的基础上,进一步研究优化激光偏振等参数对加工形貌连续性的影响,提出氮气辅助加工改进方法,获得大面积规整无碎屑沉积的类光栅结构表面,也是目前为止飞秒激光直写技术在硅上直接获得的最优质量大表面光栅结构。并结合镀膜和热处理结合的创新方法,在其结构上获得沉积的金纳米颗粒阵列微纳复合结构,实现了表面增强拉曼(SERS)基底的制备。本论文主要的研究工作和创新点可概括如下:(1)使用飞秒脉冲激光在单晶硅材料表面制备大面积、超规整的微纳级的类光栅结构。实验分析发现:烧蚀深度,连续性和形貌质量等与激光偏振方向、脉冲总能量、扫描速度、扫描间隔及加工环境等参数息息相关。本文研究发现,采用10×物镜,以低速、小间隔竖扫方式使扫描方向垂直于偏振方向等系列措施,并辅助以高压N2吹屑装置,使光栅结构的加工精度和连续性得到巨大提高。(2)创新性的采用飞秒激光加工、溅射镀膜和热处理的复合方法,有效地制备SERS活性基底。在上述制备的规整光栅结构上溅射一层纳米级金膜,通过热处理在形成金纳米粒子自组装有序阵列,实现高效、均匀且稳定的SERS基底制备。研究表明在膜厚为5nm时,经过马沸炉1000℃保温1h后,所得SERS活性基底的拉曼增强因子高达9.2×107,在空气中放置一个月后衰减仍不超过6%的高稳定性。
[Abstract]:A lot of interesting phenomena in nature formed millions of years of evolution, house lizard can butterfly wings and lotus phenomenon, colorful fly over the walls triggered deep research of scientific research personnel. It is found that these special phenomena are related to the surface structure of biological tissues, which are composed of regular and ordered micro and nano structures. These micro and nano structures change the mechanical, optical and hydrophobic properties of materials. Therefore, it is of great significance to seek the efficient and practical preparation technology of the functional surface structure of micro nano composite. In recent years, with the rapid development of ultra fast laser technology, femtosecond laser has come to the fore in the manufacturing direction of functional surface microstructures. Femtosecond laser processing has the characteristics of high precision, little crack and small heat impact zone, which makes it possible to prepare regular and ordered micro nano structure surface. Because the pulse width of femtosecond laser is smaller than the electron lattice relaxation time in the previous changes have been completed in the crystal material absorption of laser energy, the electron and lattice in non-equilibrium state, it is this nonequilibrium and nonlinear effect, lay the foundation for the realization of micro nano processing. Based on the theoretical and Experimental Research on femtosecond laser processing of predecessors, further study the influence of laser parameters on the optimal polarization processing morphology continuity, proposed nitrogen assisted machining method, surface grating structure for large area without regular clastic sediments, also is the optimal quality of large surface grating structure so far femtosecond laser direct writing the technology obtained directly on silicon. Combined with the innovative method of coating and heat treatment, the gold nanoparticle array micro nano composite structure was obtained, and the surface enhanced Raman (SERS) substrate was prepared. The main research and innovation in this paper can be summarized as follows: (1) using large femtosecond pulse laser to fabricate large area and super regular grating structure on the surface of monocrystalline silicon. Experimental analysis shows that ablation depth, continuity and morphology quality are closely related to parameters such as laser polarization direction, total pulse energy, scanning speed, scanning interval and processing environment. In this paper, a series of measures such as low speed and small interval vertical scanning are used to make the scanning direction perpendicular to the polarization direction and so on. With the aid of the high pressure N2 scraping device, the machining accuracy and continuity of the grating structure can be greatly improved by using 10 * objective lens. (2) an innovative composite method of femtosecond laser processing, sputtering coating and heat treatment is used to effectively prepare the SERS active substrate. On the above structured grating structure, we have sputtered a layer of nanometer gold film, and formed a self-assembled ordered array of gold nanoparticles by heat treatment to achieve an efficient, uniform and stable SERS substrate. Research results show that the film thickness is 5nm, after boiling 1000 DEG C for 1h, the SERS Raman active substrate enhancement factor of up to 9.2 x 107, attenuation of high stability is still less than 6% placed in air after a month.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB306

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