Effects of Annealing Temperature on Morphology and LSPR Sensing Performance of Au Nanostructures

Localized Surface Plasmon Resonance (LSPR) stands out as a powerful sensing method, where nanostructures can be formed by depositing a thin layer of metal onto a substrate followed by Rapid Thermal Annealing (RTA). This study investigates the influence of annealing temperature on the morphology, optical properties, and sensitivity of gold nanostructures fabricated on glass substrates. Utilizing thermal annealing, gold thin films were treated at temperatures ranging from 550°C to 850°C to create distinct nanostructures, which were evaluated using scanning electron microscopy (SEM) and extinction spectra measurements. The analysis revealed a significant impact of annealing temperature on the LSPR characteristics, including a blue shift in the LSPR peak and changes in the full width at half maximum (FWHM) as nanostructure uniformity improved. Finally, we conducted measurements on different chips using glycerol-water solutions of various concentrations, observing that the sensitivity decreased with the annealing temperature. This research offers critical insights into the enhancement of LSPR-based sensors through precise manipulation of nanostructure formation, highlighting the pivotal role of temperature control.