Surface-enhanced Raman scattering from a hexagonal lattice of micro-patterns of vertically aligned Ag nanorods

Aligned Ag nanorods were prepared by glancing angle deposition on micro-patterns of silicon fabricated by electron beam lithography, forming hexagonal lattices. Excited by a 633 nm He–Ne laser, Raman scattering of Rhodamine 6G molecules on the hexagonal lattices has been investigated. The enhancement of the Raman signals by the hexagonal lattices was found to be dependent on the separation distance of the micro-patterns, i.e. it reached the maximum when the patterns are separated by ∼200 nm or closely packed, suggesting a coupling effect at the micro-nano scales. This study also provides an idea to further enhance the Raman scattering.