Broad band structures for surface enhanced Raman spectroscopy are disclosed herein. Each embodiment of the structure is made up of a metal layer, and a dielectric layer established on at least a portion of the metal layer. The dielectric layer has a controlled thickness that varies from at least one portion of the dielectric layer to at least another portion of the dielectric layer. Nanostructures are established on the dielectric layer at least at the portion and the other portion, the nanostructures thus being configured to exhibit variable plasmon resonances.