Refractory nanoscale plasmonic junctions of Titanium Nitride and Niobium.*

Plasmonic tunnel junctions have great potential in the realization of nanoscale light-emitting devices and commonly used materials for these devices are metals such as gold and aluminum owing to their attractive optical properties in the visible range. A major drawback to their use is the unstable optical properties of their nanostructures at high current densities and elevated temperatures due to atomic motion, which hinders eventual device applications.  As such, it is imperative to consider refractory alternatives that guarantee the geometric stability of the light-emitting junctions at high temperatures and mimic the optical properties of noble metals in desired wavelength regimes. Here, we present preliminary results from our study of tunnel junctions composed of refractory materials; TiN and Nb that have demonstrated desirable plasmonic responses similar to gold in the red and near-infrared regime.