DERS substrate based on NERS-SERS interaction in integrated microfluidic detection.

The systematic simulation study of a structure with nanogap-enhanced Raman scattering and surface-enhanced Raman scattering (NERS-SERS) substrate is presented. This double-enhanced Raman scattering (DERS) substrate with coupling between the localized surface plasmons of noble metal nanosphere colloids and surface plasmon polaritons of a 1D sinusoidal noble metal nanograting is analyzed. With the excitation light wavelength at 785 nm, the key structure parameters of noble metal nanospheres and sinusoidal noble metal nanogratings are deduced by FDTD. With the optimal DERS substrate, the SERS enhancement factor (EF) can be 9 orders of magnitude as possible. The DERS substrate was fabricated, and an extra SERS effect was demonstrated by experiments. This DERS substrate will be integrated with microfluidics in the next work, with the purpose of in situ, real-time, continuous detection of trace water soluble gas-phase or airborne agents, such as trace explosives in air.