单晶银盘在表面增强拉曼散射中的应用

发布时间：2018-03-19 09:26

  本文选题：表面等离激元　切入点：单晶银盘　出处：《南京大学》2017年硕士论文　论文类型：学位论文

【摘要】：表面等离激元(SurfacePlasmons,SPs)是由光照射在金属表面而形成的一种自由电子集体振荡模式。它在金属表面亚波长范围内会产生非常强的束缚电场,表面等离激元的增强电场效应使得其在表面增强拉曼散射(Surface enhanced Ramanscatterring,SERS)中得到应用。而且伴随微纳米加工技术的不断发展和改进,加工精细度和可控性得到优化和提升,使得加工金属纳米结构和SERS衬底的制备更加容易。本文主要从实验上用单晶银盘做表面增强拉曼散射衬底,研究金属表面等离激元在表面增强拉曼散射中增强效果。由于表面等离激元在金属表面传播时的损耗比较大,单晶银盘是我们在样品制备方面进行的改进,以减少损耗,提高其SERS增强效果。我们在银盘上设计了几种周期性纳米结构,能够产生不同模式的表面等离极化激元,以及不同的电场分布,研究其SERS增强效果。1.介绍了单晶银盘生长方法以及对其进行了表征。我们利用化学液相生长法生长单晶银盘,生长出来银盘的直径大小有数百微米,甚至一个毫米,厚度也达到几个微米。我们用原子力显微镜测量表征银盘表面的形貌及粗糙度,同时从实验上测量了金属表面等离激元的传播长度。2.我们先从理论上分析简单一维光栅结构光学性能,并用时域有限差分法(finite difference time domain,FDTD)模拟出光栅表面电场分布情况以及强度大小,优化结构参数,以获得较高的电场增强效果。实验上,我们在单晶银盘上加工周期性纳米结构,并测量了结构的光色散谱,研究其光学性能。最后在其表面覆盖一层单分子拉曼探针分子,得到比较好的拉曼增强效果,增强因子达到105～106。我们还研究了二维结构的拉曼散射增强效果。
[Abstract]:The surface plasmon surface plasmonium (SPs) is a free electron collective oscillating mode formed by light irradiation on the metal surface. It produces a very strong binding electric field in the subwavelength range of the metal surface. The enhanced electric field effect of surface isoexcitators makes it widely used in surface-enhanced Raman scattering surface enhanced Ramanscatterring SERS. With the continuous development and improvement of micro-nano fabrication technology, the fineness and controllability of the surface are optimized and improved. It makes it easier to fabricate metal nanostructures and SERS substrates. In this paper, a single crystal silver disk is used as a surface-enhanced Raman scattering substrate. The enhancement effect of surface isoexcitons on surface enhanced Raman scattering has been studied. Because the loss of surface isotherms propagating on metal surface is relatively large, the single crystal silver disk is an improvement in sample preparation to reduce the loss. We have designed several periodic nanostructures on the silver disk to produce different modes of surface isobaric polaritons, as well as different electric field distributions. The growth method of single crystal silver disk and its characterization were introduced. We used the chemical liquid growth method to grow single crystal silver disk. The diameter of the silver disk was hundreds of microns or even one millimeter. The thickness is also several microns. We use atomic force microscopy to measure the surface morphology and roughness of the silver disk. At the same time, the propagation length of the isoexcitators on the metal surface is measured experimentally. Firstly, we theoretically analyze the optical properties of the simple one-dimensional grating structure. The electric field distribution and intensity on the surface of the grating were simulated by finite difference time-domain method (FDTD), and the structural parameters were optimized to obtain a higher electric field enhancement effect. In the experiment, we fabricated periodic nanostructures on a single crystal silver disk. The optical dispersion spectrum of the structure was measured and its optical properties were studied. Finally, a single molecule Raman probe molecule was coated on the surface of the structure, and a good Raman enhancement effect was obtained. The enhancement factor reaches 105 ~ 106.We also study the enhancement effect of Raman scattering in two-dimensional structure.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.122;O657.37
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本文编号：1633658