Improved Surface Enhanced Raman Scattering Based on Hybrid Au Nanostructures for Biomolecule Detection

We report the use of highly ordered, dense, and regular arrays of in-plane silicon nanowires as building blocks to produce highly sensitive and well-reproducible surface-enhanced Raman scattering (SERS). A combination of Au nanospheres (AuNPs) and Au coated silicon nanowires (AuSiNWs) was found to exhibit one order higher enhancement of SERS signal compared with that of the normal AuSiNWs substrate. The experimental results were further evidenced by simulating the electrical field distributions using 3-D finite-difference time-domain (3-D-FDTD). The prominence and potential applications of biosensors using AuNPs/AuSiNWs arrays were demonstrated by the improved sensitivity in detecting SERS signal of 4, 4'-Bipyridine.