Fig. 3From: Controllable Fabrication of Au-Coated AFM Probes via a Wet-Chemistry Procedurea The AFM image of Au substrate. b Schematic diagram of a TERS experiment. c Raman spectrum of Nile blue (NB) monolayer with tip retracted. d Raman spectrum detected by the probes in Fig. 2,a–c. e Raman spectrum detected by the probe in Fig. 2e. f Raman spectrum detected by the probe in Fig. 2dBack to article page