Fig. 1. Schematic fabrication process of SERS substrates.

Fig. 2. (a) SEM image and (b) AFM profile of the surface morphology written on silicon samples. The scale bar represents 2 μm.

Fig. 3. SEM images of NPs (a) on flat silicon surface and (c) on the ripple structure of 10 nm Au film dewetting; (b) and (d) are size distribution of NPs, respectively.

Fig. 4. (a) SERS spectra of different processing substrate. Red: FS+NPs area with 10−6 mol/L R6 G; Blue: FS + Film with 10−6 mol/L R6G; Green: NPs with 10−6 mol/L R6G; Black: fs laser-machined silicon with 10−2 mol/L R6G. (b) Raman map image of 20μm×20μm areas on the SERS substrates.

Fig. 5. SERS spectrum on fs laser-machined, gold-coated, thermal dewetting substrates coating different thicknesses of films.

Fig. 6. EFs of SERS signal at 1361cm−1 on fs laser-machined, gold-coated, thermal dewetting substrates coating different thicknesses of gold films. (a)–(e) scale bars represent 500 nm, (f) and (g) represent 200 nm.