Combination of Nanoholes with Metal Nanoparticles–Fabrication and Characterization of Novel Plasmonic Nanostructures

Small metal nanostructures, especially gold and silver nanoparticles, are known for their interesting optical properties caused by plasmonic effects. Molecular plasmonics, a combination of these optically active nanostructures with the molecular world, opens new possibilities for bioanalytics and (bio-) nanophotonics. Isotropic or anisotropic, homogeneous or heterogeneous metal nanoparticles provide a platform for different, highly defined functional units with interesting optical properties such as plasmon waveguides or molecular beacons. Nanohole arrays in metal layers are another promising component for nanophotonics. New photonic materials were realized from combinations of single metal nanoparticles with individual nanoholes in metals. Atomic force microscopic imaging was used to determine the particle location as well as the lateral dimensions and the topography of the resulting structures. Besides ultramicroscopic characterization of the nanoarrangements, such as nanoparticles positioned in nanoholes, far-field optical methods were also applied to investigate their optical properties.