Surface-enhanced Raman spectroscopy (SERS) is a spectroscopic technique where Raman scattering is boosted primarily by enhanced electric field due to localized surface plasmon resonance.1 With advances in nanofabrication techniques, SERS has attracted great attention for label-free molecular sensing and imaging.2,3 However, the practical use of SERS has often encountered a couple of inherent issues. The first one is regarding a molecule transfer step where target molecules need to be within the close proximity of an SERS-active surface by either mixing with nanoparticles or coating onto surface-bound nanostructures. In other words, target molecules are required to be transferred from non-SERS-active surfaces to SERS-active ones, normally in the solution phase, which can be problematic due to issues such as surface affinity variability and uncertainty, competitive adsorption among different molecules, and contamination issues, causing irreproducible results and erroneous or biased interpretations. More importantly, if the spatial distribution of molecules on the surface prior to the transfer step is of importance, such information is completely lost. Practically, solution-phase processes are relatively more labor and time consuming and require a “wet” laboratory. Furthermore, SERS measurements are always restricted to molecules adsorbed on metals such as Ag, Au, and Cu.