Gap Plasmons Multiple Mirroring from Spheres in Pyramids for Surface-Enhanced Raman Scattering
Gap Plasmons Multiple Mirroring from Spheres in Pyramids for Surface-Enhanced Raman Scattering
复制标题
DOI：
10.1021/acsphotonics.6b00631
复制
发表时间：
2016-12-01
期刊：
影响因子：
7
通讯作者：
Delaunay, Jean-Jacques
中科院分区：
文献类型：
--
作者：
Lee, Yaerim;Kamal, A. Syazwan A.;Delaunay, Jean-Jacques
获得高密度规则纳米间隙的可靠制造技术对于超灵敏表面增强拉曼散射（SEAS）是至关重要的。然而，纳米结构之间产生的纳米间隙受到缺乏可控性的影响。以球膜结构为出发点，其简单的制造技术和良好的控制间隙，我们提出了一种新的纳米结构相结合的Au纳米球和倒金字塔孔。所提出的纳米结构是通过将Au纳米球捕获在反金字塔孔阵列中以在纳米球与反金字塔之间的接触点附近产生多个、均匀且可再现的几何间隙来获得的。组合的纳米结构，被称为SIP（球在金字塔），支持增强等离子体杂交由于镜像的间隙等离子体，并诱导更强的电磁增强法向入射时相比，接触球膜结构。在对比的球膜结构表现出最大的增强斜入射，SIP实现了最大的增强在法向入射。来自SIP阵列的有效等离子体激元杂交维持的Sers强度比传统接触球膜结构强9倍，并且实现了具有0.6-0.8 nm厚间隔层的球-间隔层-膜结构获得的总电磁场增强的64%。
A reliable fabrication technique for obtaining a high density of regular nanogaps is critical for ultrasensitive surface-enhanced Raman scattering (SEAS). However, nano gaps produced between nanostructures have suffered from the lack of controllability. Taking the sphere-film structure as a starting point for its straightforward fabrication technique and well-controlled gaps, we propose a novel nanostructure by combining Au nanospheres and inverse pyramidal holes. The proposed nanostructure is obtained by trapping Au nano spheres in inverse pyramidal hole arrays to create multiple, uniform, and reproducible geometrical gaps near the contact points between the nanospheres and the inverse pyramids. The combined nanostructure, referred to as SIP (spheres in pyramids), supports augmented plasmon hybridization due to mirroring of gap plasmons and induces much stronger electromagnetic enhancement at normal incidence when compared to the contacting sphere-film structure. In contrast to the sphere-film structure exhibiting a maximum enhancement for slant incidence, the SIP achieves a maximum enhancement at normal incidence. The effective plasmon hybridization from SIP arrays sustains SERS intensities 9 times stronger than those of conventional contacting sphere-film structures and achieves 64% of the total electromagnetic field enhancement obtained from the sphere-spacer-film structure with a 0.6-0.8 nm thick spacer.