Top-up fabrication of gold nanorings

A simple method for the fabrication of gold nanorings with reliable material composition and reproducible morphology that relies on a combination of top-down and bottom-up techniques is presented. Here, lithographically defined hole arrays are used as templates for the deposition of gold nanoparticles. The resulting gold nanoparticle rings are joined by electroless deposition of gold, thereby leading to the formation of gold nanoring arrays that show plasmonic resonance in their optical spectra at theoretically predicted wavelengths. In addition, the gold nanorings can be released from the template by extensive rinsing with water, thereby enabling their further functionalization or assembly and the re-use of the template for the preparation of more nanorings.