Fabrication of free-standing plasmonic nanoantennas with application for optical break junctions

We report the fabrication of plasmonic nanoantennas with dimensions in the 200 - 300 nm range, suspended across a nano-undercut, which will be used for the investigation of the optical properties of break junctions. Nanochannels, fabricated using e-beam lithography with subsequent pattern transfer into a fused silica substrate, are initially filled with copper serving as a sacrificial infill in order to prevent the suspended nanoantennas to collapse into the channel during the fabrication process. Finally, the sacrificial copper infill is removed in order to suspend the central part of the nanoantennas. It has been shown that the fabricated structures can be broken using a break junction configuration.