Abstract: The present invention relates generally to plasmonic structures, methods for making them, and devices including them. In one aspect, a plasmonic structure includes a plurality of metal particles disposed on a substrate; and one or more metal structures electrically coupled to and disposed on a surface of each of the plurality of metal particles. The metal structures have a structure that is different than the structure of the metal particles. The metal structures can be grown, for example, by electrodeposition on the metal particles. Growth of such metal structures can tune the response of the plasmonic structure.