Department of Photonics Engineering, Technical University of Denmark , DK-2800 Kongens Lyngby, Denmark.
Nano Lett. 2013 Oct 9;13(10):4690-6. doi: 10.1021/nl402120t. Epub 2013 Sep 11.
The combination of graphene with noble-metal nanostructures is currently being explored for strong light-graphene interactions enhanced by plasmons. We introduce a novel hybrid graphene-metal system for studying light-matter interactions with gold-void nanostructures exhibiting resonances in the visible range. Enhanced coupling of graphene to the plasmon modes of the nanovoid arrays results in significant frequency shifts of the underlying plasmon resonances, enabling 30% enhanced absolute light absorption by adding a monolayer graphene and up to 700-fold enhancement of the Raman response of the graphene. These new perspectives enable us to verify the presence of graphene on gold-void arrays, and the enhancement even allows us to accurately quantify the number of layers. Experimental observations are further supported by numerical simulations and perturbation-theory analysis. The graphene gold-void platform is beneficial for sensing of molecules and placing Rhodamine 6G (R6G) dye molecules on top of the graphene; we observe a strong enhancement of the R6G Raman fingerprints. These results pave the way toward advanced substrates for surface-enhanced Raman scattering (SERS) with potential for unambiguous single-molecule detection on the atomically well-defined layer of graphene.
目前，人们正在探索将石墨烯与贵金属纳米结构结合，以增强等离子体增强的光-石墨烯相互作用。我们引入了一种新型的混合石墨烯-金属系统，用于研究具有可见光范围内共振的金-空纳米结构的光物质相互作用。通过在纳米空阵列的等离子体模式中增强石墨烯的耦合，可以显著改变等离子体共振的频率，从而使单层石墨烯的绝对光吸收增强 30%，石墨烯的拉曼响应增强 700 倍。这些新的视角使我们能够验证金-空阵列上石墨烯的存在，并且增强甚至可以准确地定量层数。实验观察结果得到了数值模拟和微扰理论分析的进一步支持。石墨烯金-空平台有利于对分子的传感，并且可以将 Rhodamine 6G（R6G）染料分子置于石墨烯顶部；我们观察到 R6G 拉曼指纹的强烈增强。这些结果为表面增强拉曼散射（SERS）的先进衬底铺平了道路，具有在原子定义明确的石墨烯层上进行单分子检测的明确潜力。
