TY - GEN A1 - Reiter, Sebastian A1 - Ratzke, Markus A1 - Nitsch, Paul-Gregor A1 - Mai, Christian A1 - Spirito, Davide A1 - Corley-Wiciak, Agnieszka Anna A1 - Wenger, Christian A1 - Fischer, Inga A. T1 - Optical response of titanium nitride plasmonic nanohole arrays : impact of square and hexagonal array geometry, pitch, and nanohole diameter T2 - Plasmonics N2 - Plasmonic nanohole arrays (NHAs) exhibit extraordinary optical transmission (EOT) evoked by resonant excitation of surface plasmons at an excitation wavelength, which is highly sensitive to changes in refractive index in the surrounding dielectric. This can enable the use of plasmonic NHAs in on-chip refractive index sensors. Such sensors can be realized on the cost-effective silicon platform by the integration of a plasmonic NHA and a Ge photodetector, provided that complementary metal–oxide–semiconductor (CMOS)-compatible materials are used for their fabrication. Titanium nitride (TiN) as a biocompatible and CMOS-compatible plasmonic transition metal nitride is well-suited for integration on the silicon platform; however, the comparatively large losses within the material require geometry optimization strategies in order to improve the optical properties of TiN NHAs for sensing. In this work, we investigated different TiN NHA geometries both in experiment and simulation. We extensively characterized square and hexagonal arrays with varying pitches and nanohole diameters and provide a detailed comparison of their optical properties. We also discuss characterization results for surface refractive index changes imposed by depositing a thin Al2O3 layer on top of the NHAs. While we do not observe a clear advantage of hexagonal arrays compared to square arrays for sensing, our results highlight the importance of geometry optimization for TiN NHAs integrated with devices. KW - Plasmonic nanohole array KW - Titanium nitride KW - Hexagonal array KW - Square array KW - Nanohole diameters Y1 - 2025 UR - https://link.springer.com/article/10.1007/s11468-025-02934-4 U6 - https://doi.org/10.1007/s11468-025-02934-4 VL - 20 SP - 8825 EP - 8834 PB - Springer CY - New York, NY ER -