Fig. 4From: Observation of single-molecule Raman spectroscopy enabled by synergic electromagnetic and chemical enhancementExperimental characterization of SM-SERS substrate. a Raman spectra of RhB with variable concentration in SM Raman base. b Raman mapping of the intensity at 1650 cm−1 peak of RhB at concentrations 10–6 ~ 10–20 MBack to article page