Controllable Fabrication of Au-Coated AFM Probes via a Wet-Chemistry Procedure

a Illustration of the wet-chemical procedure for preparing an AFM-based tip-enhanced Raman spectroscopy (AFM-TERS) probe. b A commercial Si AFM probe with the apex size <？15 nm. c Silanized probe with the apex diameter of ~？20 nm. d Au@AFM probe after a 5 min immersion and apex diameter of 25 nm. e Energy dispersive spectrometer (EDS) of the probe in