Multilayer Graphene with a Rippled Structure as a Spacer for Improving Plasmonic Coupling

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• 作者：Khang June Lee ; Daewon Kim ; Byung Chul Jang ; Da-Jin Kim ; Hamin Park ; Dae Yool Jung ; Woonggi Hong ; Tae Keun Kim ; Yang-Kyu Choi and Sung-Yool Choi
• 刊名：Advanced Functional Materials
• 出版年：2016
• 出版时间：July 25, 2016
• 年：2016
• 卷：26
• 期：28
• 页码：5093-5101
• 全文大小：1982K
• ISSN：1616-3028

文摘

The plasmonic coupling, the enhanced electromagnetic field occurring through a uniform and small separation between metallic particles, is required for better application to localized surface plasmon resonance. Graphene has been studied as a good spacer candidate because of its precise controllability at subnanoscale. Here, the enhancement of plasmonic coupling among metallic nanoparticles (NPs) uniformly spread out on both sides of a graphene spacer is experimentally and simulatively investigated. Additionally, the post-evaporated flat structure is rippled along one direction to reduce the separation between nanoparticles. As the amount of rippling increases, the enhancement factor (EF) of the plasmonic coupling increases almost linearly or quadratically depending on the size of nanoparticles. Such a highly rippled nanostructure is believed to not only increase the plasmonic coupling in either side of the spacer but lead to a higher density of “hot spots” through the spacer gap also. The observed EFs of a structure with the MLG spacer are consistent with the simulation results obtained from the classical electrodynamics. On the other hand, the SLG case appears to be inconsistent with such a classical approach, indicating that the plasmon tunneling through the thin barrier is prevalent in the case of the SLG spacer.