Fig. 3From: A Novel SERS Substrate Platform: Spatially Stacking Plasmonic Hotspots Filmsa Raman spectra of the single-layer and dual-layer porous Au film structures and ultrathin Au film. b Intensity changes of several typical Raman peaks observed in the three Raman curves in a. The sputtering time for each layer of porous Au films and film is 19 sBack to article page