Nanorod decorated nanowires as highly efficient SERS-active hybrids

Abstract

In order to propel surface enhanced Raman scattering (SERS)-based sensing into the real world, novel SERS-active nanostructure designs that enable facile, scalable, cost-effective, highly efficient and homogenous SERS substrates are paramount. We demonstrate the facile fabrication of highly efficient SERS-active 3D nanohybrids based on vertically aligned zinc oxide nanowires uniformly decorated with gold nanorods. The dramatic enhancement of the surface area (nearly 20 times) and hence the number of plasmonic nanostructures within the incident laser foot print results in more than three orders of magnitude increase in SERS intensity compared to planar SERS substrates. The SERS enhancement factor was found to be ∼3 × 10⁷ with a detection limit of sub-pM for a non-resonant analyte. Apart from excellent sensitivity, the nanohybrids also exhibited excellent lateral and vertical homogeneity in SERS activity. We believe that under optimal conditions these nanohybrids can surpass the best 2D substrate designs in SERS enhancement and homogeneity.