TiN Plasmonic Metamaterial Arrays Fabricated at Low Temperatures on Versatile Substrates

Transition metal nitrides (TMNs) have emerged as promising alternative materials for plasmonic and optoelectronic applications in the visible and near-IR spectral ranges. However, the deposition of TMNs with optical properties suitable for plasmonic applications typically requires high temperatures (>800 °C). In this work, we use high-power impulse magnetron sputtering (HIPIMS) to deposit plasmonic TiN thin films at room temperature, without intentional heating. HIPIMS increases the energies of metal ions and dissociated nitrogen (N¹⁺) in the flux, enabling the low-temperature deposition of high-quality TiN thin films on a range of industrially relevant substrates, including flexible polymer substrates. We demonstrate that the room-temperature deposition method can be used to produce plasmonic TiN nanoarrays via colloidal lithography, with tunable shapes and dimensions, creating features on the order of 100-500 nm. We characterize the optical response and plasmonic performance of these nanoarrays, demonstrating tailorable resonances in the visible and NIR spectral range, in agreement with optical simulations reported here.