The Korean Society of Surface Science and Engineering

In this study, we developed a cost-effective and stable surface-enhanced Raman scattering (SERS) substrate using porous silver (Ag) thin films fabricated via gas flow sputtering (GFS). The structural parameters including deposition pressure and film thickness were systematically optimized to enhance localized surface plasmon resonance (LSPR) effects by controlling nanogap formation. The porous Ag film deposited at 50 mTorr with a thickness of 200 nm exhibited the highest Raman enhancement (EF = 4.11 × 10⁵). To further improve the SERS performance, dense Ag and dielectric interlayers (Al₂O₃, SiO₂) were inserted under the porous Ag layer, which created additional electromagnetic hot spots through multilayer formation. Among these, the dense Ag-SiO₂-porous Ag structure achieved the highest enhancement factor of 3.51 × 10⁶. Moreover, the SiO₂ interlayer significantly suppressed signal degradation caused by oxidation and sulfidation, maintaining over 89.9 % of its initial signal intensity after 16 weeks in ambient conditions. These results demonstrate the feasibility of sputtered multilayer SERS substrates for reliable, high-sensitivity molecular detection platforms.

키워드 SERS, Silver, Dielectric, Nanogap, Sputtering