Fig. 1
Characterization for synthesized SC Au flakes and schematics of experimental setup. a SEM images for a hexagonal SC gold flake together with deposited electrodes at the corner. The scale bar here is 3.5 μm. b, c Electron diffraction pattern of the 20 nm SC gold flake and 20 nm evaporated PC Au flake, respectively. The scale bar is 10 nm−1. d AFM scanned height profile along the dashed line of the 20 nm thick SC flake in (a). e Focused ion beam (FIB) milling was used to cut a nanowire from the SC flake. The scale bar is 2.5 μm. f 3D sketch of the setup. g SEM image of an electromigrated nanowire, showing a nanogap for highly enhanced local surface plasmonic responses. The scale bar is 300 nm
