A dedicated multilayer technique for the fabrication of three-dimensional metallic nanoparticles

High resolution electron-beam lithography has been applied to the fabrication of three-dimensional metallic nanostructures. The herein developed fabrication process, which is demonstrated at the example of two ensembles of complex nanoscale particles, comprises a dedicated combination of multilayer electron-beam exposure, vacuum evaporation, lift-off and dry etching. The designs of the two nanostructures rely on the principles of a low degree of spatial symmetry and a high degree of chirality, respectively. Their optical properties are evaluated by means of far-field transmittance spectroscopy. Our fabrication technique delivers an excellent quality of miniaturized three-dimensional nanostructures and yields great potential to be extended towards the fabrication of large-area optical metamaterials composed of truly three-dimensional metallic nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.