Concentric dot-ring metal nanostructures prepared by colloidal lithography

Abstract

A large scale production of well-defined metallic nanostructures represents an important step for a real application of plasmonic technology. Here, we report about a development in colloidal lithography for the production of metallic nanostructures of flexible geometry, which can be changed between disks, cones, rings and even concentric dot-ring structures. We show that the simple spherical colloidal mask—applied to produce metallic disks—can be modified by chemical and plasma etching process to produce either ring or dot-ring structure. Furthermore, etching of the colloidal mask leads to cone shaped metallic nanostructures. All these structures are prepared by the same fabrication steps, and different geometries are achieved just by variation of the fabrication parameters. We are able to prepare homogenously dispersed nanostructures (with defined density) with a height between 20 and 50 nm and a lateral dimension between 100 and 200 nm. In the realized nanostructures, the thickness of the ring is 46.2 ± 4.4 nm and the dot structure has an outer diameter of ∼217 nm.