Large-area SERS chip based on periodic striped metal-insulator-metal structures fabricated by laser interference lithography

LIL enables straightforward, low-cost fabrication of large-area SERS chips. • Periodic nano-stripe Ag/SiO 2 /Au structures strengthen local electromagnetic fields. • SERS substrate with periodic stripe MIM structures achieves an EF exceeding 10 10 . • Integrating MIM substrates with microfluidics enables real-time, in situ detection. Large-area, low-cost, good-reliability, and high-sensitivity surface-enhanced Raman scattering (SERS) substrate is a prerequisite for such devices to enter the market. In this work, we present a SERS substrate consisting of a vertical metal-insulator-metal (MIM) nano-stripe pattern fabricated by laser interference lithography (LIL). The proposed SERS substrate exhibits high sensitivity, reproducibility, and stability, with the characteristic Raman signals of rhodamine 6   G (R6G) experimentally detected at concentrations down to 10 -8   M and an enhancement factor (EF) exceeding 10 10 . Furthermore, by integrating the SERS substrate with a microfluidic chip enabled the construction of a real-time, in situ and non-destructive detection device, whose SERS performance was validated via Raman spectra tests of melamine and malachite green. Overall, this work comes up with an efficient strategy for fabricating sensitive and reproducible SERS substrates that hold considerable promise for advancing biochemical sensors equipped with SERS functionality.