Deposition of alternative plasmonic ZrHfN thin films via closed-field dual-cathode DC unbalanced magnetron sputtering for enhanced SEF substrate applications

We present the preparation of zirconium hafnium nitride thin films as an alternative plasmonic sensing material. The ZrHfN thin films were deposited by closed-field dual-cathode DC unbalanced magnetron sputtering without an external substrate heating/biasing. A comprehensive investigation into the effect of zirconium sputtering current on the physical structural, and chemical compositions was systematically characterized by grazing-incidence X-ray diffraction, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Our results indicate that the optimal ZrHfN thin films deposited at 500 mA-I_Zr exhibit good crystallinity and high surface roughness, which presents excellent surface-enhanced fluorescent substrate performance for detecting rhodamine 6G at a limit of detection of 5.99 × 10⁻⁸ M, an enhancement factor of 15.62 ± 0.79-fold and displaying reusability through 25 cycles. These findings suggest promising prospects for developing ZrHfN-based SEF sensor chips for diverse applications in the future.