One-step fabrication of nanostructures by femtosecond laser for surface-enhanced Raman scattering

Abstract

This paper reports an efficient fabrication of nanostructures on silicon substrates for surface-enhanced Raman scattering (SERS). Silicon wafer substrates in the aqueous solution of silver nitrate were machined by the femtosecond laser direct writing to achieve simultaneously in one-step the generation of grating-like nanostructures on the surface of the substrate and the formation of silver nanoparticles on the surface of the nanostructures via the laser-induced photoreduction effect. Parametric studies were conducted for the different concentrations of aqueous silver nitrate solutions and scanning speeds. The enhancement factor of the SERS is found to be higher than 10(9). The patterning technique provides an opportunity to incorporate the SERS capability in a functional microchip.

Two-Step Photonic Reduction of Controlled Periodic Silver Nanostructures for Surface-Enhanced Raman Spectroscopy

“…Laser reduction techniques, where metal ions absorb photon-excited electrons and are reduced to metallic clusters for development of various nanoparticle forms (such as nanoplates, nanospheres, or aggregated into 3D metallic nanostructures) have received significant attention for enhancing SERS performance [8]. In a polymer medium such as polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA) [9,10], a grating-like nanostructure can be induced by multiple photonic reductions with femtosecond laser, producing a SERS enhancement factor of more than 10 9 [8]. 2D or 3D metallic nanoparticle patterns on substrates can be easily controlled using laser direct writing techniques as nanoparticles are only produced in laser-irradiated regions.…”

Multiphoton excitation of surface plasmon-polaritons and scaling of nanoripple formation in large bandgap materials

“…Because this method of structuring is an easy-to-implement, low-cost, top-down method which is able to fabricate periodic structures on the nanoscale without the sophisticated multi-step processes and ultrashort wavelengths needed for nano-lithography, HSFL has gained increasing attraction for practical applications. In particular, emerging fields of nanotechnology and photonics such as surface enhanced Raman spectroscopy (SERS) [11][12][13], colorization of metals [14,15], incandescent light sources [16] Up to now, the fundamental mechanisms of nanoripple formation are completely understood. Specifically, the different contributions of material transport and self-trapped excitons and plasmons as well as long-term effects like energy deposition or defect accumulation, the influence of second harmonic generation and the relationship between surface and volume structures are still the subject of controversial discussions.…”

Glass‐embedded silver nanoparticle patterns by masked ion‐exchange process for surface‐enhanced Raman scattering

“…In addition, enhanced Raman signals can be obtained from silver nanostructures fabricated by other methods, such as the Langmuir-Blodgett technique [15] and the femtosecond laser-induced photoreduction. [16] Indeed, to transfer SERS into commercial applications, simple and costeffective techniques for the preparation of SERS-active substrates are needed.…”

“…Refs. [14][15][16]), because it shows intense SERS due to a strong resonance Raman contribution and it is therefore easy to be detected in SERS experiments even at low coverage. Moreover, its spectral features have been well characterized.…”