Metallic Refractory Titanium Nitride: An alternative stable metal with tunable optical properties for high temperature plasmonic applications*

The increasing demands of high temperature plasmonic applications require a refractory plasmonic material that is more stable than commonly used metals such as gold (Au). Although a dielectric, under different deposition conditions titanium nitride (TiN) can be converted into a metal-like material that is stable at high temperatures and with plasmonic performance similar to that of Au. We produce TiN films with tunable optical properties ranging from those characteristic of a dielectric to strong metallic behavior with high negative real part of its frequency dependent dielectric function. Various nanostructures formed from both Au and TiN were characterized and compared, using Fourier Transform Infrared Spectroscopy and Scanning Near Field Optical Microscopy. TiN nano-antennas show tunable and distinct localized surface plasmon resonances that are comparable to those of Au. Moreover, the TiN nano-antennas exhibit a significantly more robust optical response after being annealed at high-temperatures, demonstrating the suitability of TiN to act as a stable metal for high temperature plasmonic applications.