Characterization of ternary ZrHfN thin films deposited by closed-field dual-cathode DC unbalanced reactive magnetron sputtering: A preliminary investigation on their reusable SERS with high thermal stability

Abstract

The zirconium hafnium nitride thin films as alternative plasmonic sensing for surface-enhanced Raman scattering substrate (SERS) were fabricated by closed-field dual-cathode DC unbalanced magnetron sputtering within a thickness range of 30–70 nm. The influence of film thickness on morphology and structural was investigated by grazing-incidence X-ray diffraction (GIXRD) and field-emission scanning electron microscopy (FE-SEM). The GIXRD results indicated that all the prepared ZrHfN thin films exhibited face-centered cubic structures. Surface-sensitive methods like X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) were employed to understand the chemical composition and the distribution of nitrogen atoms. Furthermore, the SERS performance of the ZrHfN films was evaluated using Rhodamine 6 G (R6 G) as a probe molecule. It was found that the 70-nm ZrHfN thin film demonstrated a SERS enhancement factor of 5.4 × 10⁵ and high reusability (15 cycles). Additionally, our SERS substrates exhibited high thermal stability, which maintains sensitivity after heat treatment at 250 ^οC for 10 min in air ambient. These results highlight the potential of the ZrHfN thin film as an alternative SERS sensor chip for real-world applications.