本研究利用近場光學顯微鏡(near-field scanning optical microscopy ,NSOM)應用於奈米結構之量測與特性分析，由於其架構是以剪力式之原子力顯微鏡(Atomic Force Microscope, AFM)為基礎，並且具有點光源激發以及在近場的範圍中量測，故可獲得在次波長的區域內，奈米金屬結構的表面型態(topography)和其所對應的光學影像(optical image)。
首先利用自主性結構(self-assembly monolayer ,SAM)的方法，以化學吸附及高溫退火的方式製備奈米金屬結構。在化學吸附方面，先在基板上形成3-aminopropyl-triethoxysilane(APTES)薄膜，利用正負電相吸的原理，將平均粒徑20nm之奈米金粒子吸附在基板上，奈米金粒子的吸附密度，在浸泡時間為一小時後到達飽和，這可以由穿透率和表面型態的量測得到驗證。在高溫退火方面，藉由控制金屬薄膜的厚度，可獲得不同粒徑大小之奈米金屬粒子。將10、5、3nm的金薄膜以9000C、銀薄膜以6000C，經過30min的熱退火，可成功製備平均粒徑為250、53、24nm之奈米金粒子，以及平均粒徑為138、41、23nm之奈米銀粒子。
最後利用近場光學顯微鏡，進行探針照明(tip illumination)下之穿透模式(transmission mode)的量測，發現奈米金屬結構確實對光場有近場增強的作用，並且對奈米金屬粒子的表面電漿效應，以及光纖孔徑探針將近場訊號散射至遠場的現象做ㄧ驗證。

In this dissertation, optical properties of metallic nanostructures are investigated using near-field scanning optical microscopy (NSOM). NSOM is consisted of a shear force atomic force microscope (AFM) with a metal-coated taper single mode fiber as the probe tip. Therefore, topography and optical images of the nanostructure with sub-wavelength resolution can be achieved at the same time.
The metallic nanostructures investigated in this study are fabricated by methods of chemical absorption and high temperature annealing. In the method of chemical adsorbing, the substrate surface was first functionalized with a self-assembled monolayer (SAM) of 3-aminopropyl-triethoxysilane (APTES). Au nanoparticles were subsequently absorbed on the substrate surface due to electrostatic attraction between the nanoparticles and the SAM. The Au absorption density reaches a maximum value after one hour of immersion, which is verified by both absorption measurements and secondary electron microscopy (SEM). The second method is high temperature annealing of a thin metal film. Nanoparticles with different particle size can be obtained by controlling the thickness of metallic thin film. Au nanoparticles with average size of 250、53、24nm and Ag nanoparticles with average size of 138、41、23nm can be obtained by annealing Au and Ag films of thickness of 10、5、3nm are annealed at 9000C for 30min and at 6000C for 30min, respectively.
Finally, transmission mode NSOM images of the metallic nanoparticles reveal that higher transmission occurs when illuminated with light that is on resonance with the localized surface plasmon mode of the metallic nanoparticles, which results in a brighter spot in the image. By contrary, off-resonance light results in a lower transmission intensity, which results in a dark spot in the NSOM image. Therefore, the results strongly support that localized surface plasmon from the metallic nanostructures enhance the conversion of near-field light into far-field light.

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