A tunable approach to fabricate cost-effective SERS substrates using Au nanoparticles by sputtering deposition

In this study, we investigate a simple technique in surface-enhanced Raman spectroscopy (SERS) substrate fabrication designed to decrease synthesis time, effort and cost. Sputtering is utilized to deposit a gold (Au) layer on insulating substrates, and annealing treatments are applied to agglomerate the Au atoms into the sought-after nanostructures conducive to the SERS effect. The samples are characterized by scanning electron microscopy, Raman spectroscopy, atomic force microscopy, etc. This study shows that with increasing sputtering amperage and time, the film thickness increases, and with increased annealing temperature, the surface roughness decreases while increasing the particle-to-particle distance. A quartz substrate with 10 mA current, 40 s time and annealing at 300°C produced the highest enhancement factor. Through the utilization of sputter coating and a simple annealing step, the complexity of SERS substrate synthesis can be scaled back considerably, allowing further utilization within industrial and medical settings and unlocking more potential for SERS.