Surface plasmons and SERS application of Au nanodisk array and Au thin film composite structure

A composite structure of an Au nanodisk array and an Au film is designed to excite local surface plasmons and propagating surface plasmons and generate strong resonance coupling. The finite difference time domain method was used to study the surface plasmons effect of the structure. The composite substrate of an Au disk array with a 760-nm period and a 130-nm diameter was prepared via electron beam lithography. The SERS characteristics of the substrate were studied using rhodamine 6G (R6G) as a Raman probe molecule. The Raman intensity of R6G on the substrate reached values as high as 82.9% of the first measurement intensity, after the SERS substrate had been exposed to the atmosphere for 30 days. The results show that the proposed substrate yields good uniformity, reproducibility, and stability, thereby providing an effective and feasible scheme for the detection of molecules.