Metal nanocones can exhibit several strong plasmonic resonances, which are associated with intense and accessible electromagnetic hot spots. They can thus be used to enhance light-matter interactions or to facilitate location-specific sensing while enabling separation of some non-specific contributions towards the sensing signal.
The research group of Univ.-Prof. Dr. Erik Reimhult has previously shown how functionalized nanocones inside nanopores can be used for size-selective biosensors. Such sensors could be very sensitive also in complex environments and used with very low-cost equipment. The localization of the nanoplasmonic optical resonances is the critical feature that enables this use.
Nanocones and similar 3D structures are often fabricated with the use of the so-called self-shading effect, which occurs during the evaporation of a metal film into circular nanowells. Unfortunately, a full description of a successful deposition process with all the essential details was missing in the literature.
The work performed by the group of Prof. Tomas Sikola at CEITEC with participation from the Institute for Biologically Inspired Materials presents a detailed view of the fabrication of ordered arrays of conical gold nanostructures using electron beam lithography and gold electron beam evaporation.
Our findings help to identify inherent limits for the production of wafer-scale arrays of such non-planar nanostructures. However, they also suggest new fabrication possibilities for more complicated structures, such as mutually connected nanocones for electrically addressable chips that can be used in optoelectronic biological nanosensors.
The joint research was published as an article in the journal Microelectronic Engineering as “Effect of deposition angle on fabrication of plasmonic gold nanocones and nanodiscs.”