Surface-enhanced Raman characteristics of Ag cap aggregates on silicon nanowire arrays

Abstract

A convenient nanotechnique is used to place analyte molecules between closely spaced silver-capped Si nanowires for investigating surface-enhanced Raman scattering (SERS). It is revealed that the SERS intensity (or sensitivity) is closely related to the etching time used to prepare the Si nanowires from wafer. As the etching leaves the nominal spacing between the nanowires unaffected, the observed effect can be explained based on different gaps between the Ag particles due to the different lengths of the Si nanowires. Large SERS intensity for short etching times can be elucidated in terms of the rigidity of the nanowires and the smaller SERS intensities for longer etching times can be explained by considering the bending of nanowires and the agglomeration of the Ag caps due to gravity and van der Waals forces.

Surface-Enhanced Raman Scattering of 4-Aminothiophenol Adsorbed on Silver Nanosheets Deposited onto Cubic Boron Nitride Films

“…7 Recently, considerable efforts have been directed to assemble the silver or gold nanostructures on glass, silicon, carbon, and metal material surfaces by many techniques including templates, vacuum evaporation, nanolithography, and etching. [8][9][10][11][12] The electromagnetic "hot spots" exist in the sharp features, large curvature regions, and gap sites between two particles in proximity. The above nanostructure films show significantly better stability, sensitivity, and controllability.…”

A silver nanoparticle loaded TiO2 nanoporous layer for visible light induced antimicrobial applications

“…Fig. 2a shows Raman active modes of anatase [21] crystalline TiO 2 at 399 cm −1 , 513 cm −1 and 519 cm −1 and the rutile phase at 447 cm −1 and 612 cm −1 . Generally, Ag adsorbed surfaces have an enhanced Raman signal due to the surface enhanced Raman spectra (SERS) properties of Ag.…”

Aligned silicon nanowires with fine‐tunable tilting angles by metal‐assisted chemical etching on off‐cut wafers

“…Aligned silicon nanowires (SiNWs) have drawn much interest in recent years due to their promising applications in high‐efficiency photovoltaics 1, light‐emission devices 2, 3, anti‐reflection surfaces 4, surfaces with special wetting or adhesion properties 5, 6, heat transfer devices 7 and sensing devices 8, etc. In these applications, Si as the most important semiconducting material exhibited unusual properties due to the nanoscale size effects of SiNWs.…”