Localization of the electromagnetic field in the vicinity of gold nanoparticles: Surface modification of different substrates
Localization of the electromagnetic field in the vicinity of gold nanoparticles: Surface modification of different substrates
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DOI：
10.1016/j.apsusc.2007.06.069
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发表时间：
2007-12
影响因子：
6.7
通讯作者：
P. Atanasov;N. Nedyalkov;T. Sakai;M. Obara
中科院分区：
文献类型：
--
作者：
P. Atanasov;N. Nedyalkov;T. Sakai;M. Obara
本文介绍了利用金纳米粒子附近的近电磁场增强对金属（Au）、半导体（Si）或电介质（钠石灰玻璃）基板进行纳米级改性的理论预测和实验结果。利用时域有限差分模拟技术，研究了由分离金纳米粒子或纳米粒子聚集体组成的基片在电磁波照射下的近场特性。预测了衬底材料对近场分布特性的影响。结果表明，在三种情况下，衬底表面的场均增强，但其空间分布和大小取决于衬底材料。在金属和半导体衬底的情况下，增强的近场强烈地定位于与颗粒接触点附近，在直径小于颗粒直径的区域内。在玻璃上的增强场强度比使用硅衬底的情况低一个数量级以上。基板表面近场的性质也取决于粒子的排列。对于二维金纳米粒子阵列，当粒子排列紧密时，衬底表面的增强场强度最小。随着粒子间距离的增加，近场强度增大。实验验证了所得理论结果的有效性。
Theoretical predictions and experimental results for nanosized modification of metal (Au), semiconductor (Si), or dielectric (soda lime glass) substrates using near-electromagnetic field enhancement in the vicinity of gold nanoparticles are presented. The near field properties for the system consisting of an isolated gold nanoparticle or nanoparticle aggregate deposited on the substrates, which is irradiated by electromagnetic wave, are investigated using Finite Difference Time Domain Simulation technique. The influence of the substrate material on the near field distribution characteristics is predicted. The results reveal that the field on the substrate surface is enhanced in the three investigated cases, but its spatial distribution and magnitude depend on the substrate material. In the case of the metal and semiconductor substrate the enhanced near field is strongly localized in the vicinity of the contact point with the particle, in an area with diameter smaller than the particle's one. The intensity of the enhanced field on the glass is more than an order of magnitude lower than the case of using silicon substrate. The properties of the near field on the substrate surface also depend on the particle arrangement. For a two-dimensional gold nanoparticle array, when the particles are closely arrayed, the intensity of the enhanced field on the substrate surface is minimal. With the increase of the interparticle distance the near field intensity increases. The validity of the obtained theoretical results is confirmed experimentally.