A study of noble metal films in periodic structures in relation to excitation wavelength for SERS

Surface-enhanced Raman spectroscopy (SERS) has established itself as a highly sensitive technique for biochemical detection. Despite significant research progress, most SERS substrates with single-resonant plasmonic nanostructures on planar surfaces are plagued by narrowband operational constraints in SERS performance. Herein, we design a simple periodic hexagonal nanostructure to explore the impacts of noble metal film parameters on surface plasmon distribution and electric field intensity. By studying the role of noble metals in SERS structures, we derive a method for designing nanostructures tailored to target excitation wavelengths. Periodic hexagonal nanostructures fabricated via ICP etching are employed to validate the findings, achieving relatively high detection sensitivity at excitation wavelengths of 532 nm and 633 nm, respectively.