Fig. 2
SERS characterizations of Ag@SiO2 substrates. a SERS spectra of CV on Ag@SiO2 substrates with the thickness of SiO2 layers vary from 0 to 100 nm. b Spectrum intensity calculations of CV at 1174 and 1620 cm−1 based on the interparticle distance. c SERS spectra of CV absorbed on Ag@SiO2 substrate after immersed in different concentrations of CV solution. d Normal Raman spectrum of 10−2 M CV solution on silicon wafer (1) and SERS spectrum of 10−6 M CV solution on Ag@SiO2 substrate (2)