Probing the limits of plasmonic enhancement using a two-dimensional atomic crystal probe  

作　　者：Wen Chen Shunping Zhang Meng Kang Weikang Liu Zhenwei Ou Yang Li Yexin Zhang Zhiqiang Guan Hongxing Xu 

机构地区：[1]School of Physics and Technology,Center for Nanoscience and Nanotechnology,and Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education,Wuhan University,Wuhan 430072,China [2]The Institute for Advanced Studies,Wuhan University,Wuhan 430072,China

出　　处：《Light(Science & Applications)》2018年第1期500-510,共11页光（科学与应用)（英文版）

基　　金：supported by the National Key Basic Research Program(Grant No.2015CB932400);the National Key R&D Program of China(Grant Nos.2017YFA0303504 and 2017YFA0205800);the National Natural Science Foundation of China(Grant Nos.11304233,11674256,11674255,and 11404247);the China Postdoctoral Science Foundation(Grant No.2014T70727).

摘　　要：Achieving larger electromagnetic enhancement using a nanogap between neighboring metallic nanostructures has been long pursued for boosting light–matter interactions.However,the quantitative probing of this enhancement is hindered by the lack of a reliable experimental method for measuring the local fields within a subnanometer gap.Here,we use layered MoS2 as a two-dimensional atomic crystal probe in nanoparticle-on-mirror nanoantennas to measure the plasmonic enhancement in the gap by quantitative surface-enhanced Raman scattering.Our designs ensure that the probe filled in the gap has a well-defined lattice orientation and thickness,enabling independent extraction of the anisotropic field enhancements.We find that the field enhancement can be safely described by pure classical electromagnetic theory when the gap distance is no<1.24 nm.For a 0.62 nm gap,the probable emergence of quantum mechanical effects renders an average electric field enhancement of 114-fold,38.4%lower than classical predictions.

关 键 词：DIMENSIONAL CRYSTAL RENDER 

分 类 号：TB3[一般工业技术—材料科学与工程]