M‐shaped Grating by Nanoimprinting: A Replicable,Large‐Area,Highly Active Plasmonic Surface‐Enhanced Raman Scattering Substrate with Nanogaps |
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Authors: | Zhendong Zhu Benfeng Bai Huigao Duan Haosu Zhang Mingqian Zhang Oubo You Qunqing Li Qiaofeng Tan Jia Wang Shoushan Fan Guofan Jin |
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Affiliation: | 1. State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, , Beijing, 100084 China;2. Tsinghua‐Foxconn Nanotechnology Research Center, Department of Physics, Tsinghua University, , Beijing, 100084 China;3. Key Laboratory for Micro‐Nano Optoelectronic Devices of Ministry of Education, Hunan University, , Changsha, 410082 China |
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Abstract: | Plasmonic nanostructures separated by nanogaps enable strong electromagnetic‐field confinement on the nanoscale for enhancing light‐matter interactions, which are in great demand in many applications such as surface‐enhanced Raman scattering (SERS). A simple M‐shaped nanograting with narrow V‐shaped grooves is proposed. Both theoretical and experimental studies reveal that the electromagnetic field on the surface of the M grating can be pronouncedly enhanced over that of a grating without such grooves, due to field localization in the nanogaps formed by the narrow V grooves. A technique based on room‐temperature nanoimprinting lithography and anisotropic reactive‐ion etching is developed to fabricate this device, which is cost‐effective, reliable, and suitable for fabricating large‐area nanostructures. As a demonstration of the potential application of this device, the M grating is used as a SERS substrate for probing Rhodamine 6G molecules. Experimentally, an average SERS enhancement factor as high as 5×108 has been achieved, which verifies the greatly enhanced light–matter interaction on the surface of the M grating over that of traditional SERS surfaces. |
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Keywords: | localized surface plasmons gratings near‐field enhancement nanoimprinting surface‐enhanced Raman scattering |
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