Studying Properties of Composite Nano-PAA-Au Array for the Optimal SERS Sensitivity
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The composite structure of nano-porous anodic alumina (nano-PAA) coated with noble metal layer has been demonstrated to be one kind of high-sensitive surface-enhanced Raman scattering (SERS)-active substrate. However, the experimental investigations on influences of parameters were restricted by correlation between variables. And in relevant simulation studies, nano-tips at intersections of unit edges on the surface and the metal attaching to inside walls of nano-holes which are crucial for the enhancement of electric field were commonly idealized. To obtain the optimal structure of nano-PAA-Au array for SERS applications, numerical evaluations of the electric field distributions and intensities at hotspots were carried out on a proposed precise model. The influence of structure and excitation parameters which determined the electromagnetic enhancement have been systematically investigated. The numerical data shows that the intensity and distribution of surface electric field is evidently affected by both the characteristics of nano-tips and the metal attaching to the inside wall of holes. In addition, the designed substrate was synthesized accordingly and demonstrated to be higher sensitive with an achieved enhancement factor of 1.04 × 107. The study would be helpful in designing high-sensitive SERS-active substrates.
KeywordsSurface-enhanced Raman scattering Localized surface plasmon resonance Nano-PAA-Au array Electromagnetic enhancement
This project is supported by the National Natural Science Foundation of China (Grant No. 61378083), the International Cooperation Foundation of the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2011DFA12220), the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91123030), the Key Laboratory Project of Shaanxi Education Department (Grant Nos. 14JS106 and 16JS102), the Natural Science Foundation of Shaanxi Province (Grant No. 2010JS113), and the Major Fundamental Research Project of Natural Science Fundamental Research Program of Shaanxi Province (Grant No. 2016ZDJC-15).
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