Raman systems include a radiation source, a radiation detector configured to detect Raman scattered radiation, and a Raman signal-enhancing structure. The Raman signal-enhancing structure includes a first layer of Raman signal-enhancing material, a substantially monomolecular layer of molecules disposed on at least a portion of the first layer of Raman signal-enhancing material, and a second layer of Raman signal-enhancing material disposed on at least a portion of the substantially monomolecular layer of molecules. The second layer of Raman signal-enhancing material is disposed on a side of the layer of molecules opposite the first layer of Raman signal-enhancing material. Methods of performing Raman spectroscopy include providing such a Raman signal-enhancing structure, providing an analyte on the Raman signal-enhancing structure, irradiating the analyte and the structure, and detecting Raman scattered radiation.