We have visualized surface-enhanced Raman scattering (SERS) nano-gap domains with electrostatic force microscopy (EFM). We constructed the SEAS substrate using reactive-ion etching of a polyethylene terephthalate (PET) film, with subsequent sputtering of Au onto the etched PET. Because the nano-gap is more strongly charged than the native Au-nanoparticle (NP) surface, we can identify the SEAS nano-gap due to the longer dwell time of the tapping EFM tip and the related phase shift of the signal. This produces a differentiating image contrast between the SEAS nano-gap and the Au NP surface, with a spatial resolution of similar to 14 nm. More specifically, differences in the mode-independent Raman-signal enhancement and the peak shift of an adsorbed malachite green isothiocyanate (MGITC) molecule are only observed in the smaller SEAS nano-gap (found in the surface with Ar+ -sputtered Au nano-pillars). We interpret this in terms of the differing morphologies of the underlying Au substrates and the related mechanical compressive strains, which result in charge transfer (CT)-based single-molecule Raman-reporter detection sensitivity.