Fig. 11From: A Novel SERS Substrate Platform: Spatially Stacking Plasmonic Hotspots Filmsa Sample image and b SERS mapping taken from the boundary of the fabricated sample with 37.5 s sputtering time of each layer of porous Au films. Raman spectra measured in the single c and dual-layer d porous Au films as marked with the arrowsBack to article page