Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology , Beijing 100081, P. R. China.
Laser Micro/Nano-Fabrication Laboratory, Department of Mechanical Engineering, Tsinghua University , Beijing 100084, P. R. China.
ACS Appl Mater Interfaces. 2018 Jan 10;10(1):1297-1305. doi: 10.1021/acsami.7b13241. Epub 2017 Dec 27.
Various Au nanostructures have been demonstrated to have an enhanced local electric field around them because of surface plasmons. Herein, we propose a novel method for fabricating Au nanoparticle-decorated nanorod (NPDN) arrays through femtosecond laser irradiation combined with Au coating and annealing. The nanorod cavities strongly confined light and produced an enhanced optical field in response to Au nanoparticles (NPs) introduction. The nanogap and diameter of the fabricated Au NPs significantly affected the surface-enhanced Raman scattering (SERS) performance and could be simultaneously tuned with thickness-controllable Au films and substrate morphologies. The resulting Au NPDN substrate was observed to have efficient "hot spots" for tunable SERS applications. We experimentally determined that the enhancement factor of the Au NPDN substrate reached up to 8.3 × 10 at optimal parameters. Moreover, the Au NPDN substrate showed superior chemical stability, with the greatest intensity deviation of 3.2% on exposure to air for 2 months. This work provides a promising method to fabricate tunable plasmonic surfaces for highly sensitive, reproducible, and chemically stable SERS applications.
各种 Au 纳米结构由于表面等离激元而被证明在其周围具有增强的局域电场。在此，我们提出了一种通过飞秒激光辐照结合 Au 涂层和退火来制备 Au 纳米颗粒修饰的纳米棒（NPDN）阵列的新方法。纳米棒腔强烈限制光，并产生增强的光场以响应 Au 纳米粒子（NPs）的引入。所制备的 Au NPs 的纳米间隙和直径对表面增强拉曼散射（SERS）性能有显著影响，并且可以与厚度可控的 Au 薄膜和基底形貌同时进行调整。结果表明，所得到的 Au NPDN 基底具有高效的“热点”，可用于可调谐的 SERS 应用。我们通过实验确定，Au NPDN 基底的增强因子在最佳参数下达到了 8.3×10。此外，Au NPDN 基底表现出优异的化学稳定性，在空气中暴露 2 个月后，最大强度偏差为 3.2%。这项工作为制备用于高灵敏度、可重现和化学稳定的 SERS 应用的可调谐等离子体表面提供了一种有前途的方法。
