Large-area opposing double nanocrescents-nanoparticle arrays for polarization dependent SERS effects.

[Display omitted] • A large-area Ag opposing double nanocrescents-nanoparticle array is fabricated via low-cost fabrication method. • The morphology of the crescent-shaped coupling plasmonic nanostructure can be easily tailored. • The AODCP array exhibits obvious polarization dependent SERS effects. • The AODCP array presents excellent SERS properties. An efficient fabrication route is developed to produce a large-area and highly-ordered Ag opposing double nanocrescents-nanoparticle (AODCP) array by combining the ultra-thin alumina membrane (UTAM) mask, annealing and angle deposition techniques. This strategy exhibits a controllable fabrication process of crescent-shaped plasmonic nanostructures wherein the number and orientation of the nanocrescents can be independently tuned. The localized electrical fields are extremely enhanced in the nanogaps and at the tips of the nanocrescents due to the coupling between the nanocrescents and nanoparticles, and their distributions depend on the polarization of the incident light, which are confirmed by numerical simulations. Polarization-dependent surface enhanced Raman scattering (SERS) is experimentally demonstrated on this AODCP substrate with remarkable sensitivity and reproducibility. The results suggest the proposed AODCP arrays are promising for the applications in the fields of nonlinear optics, optical sensors and surface enhanced spectroscopy. [ABSTRACT FROM AUTHOR]