Gold nanoparticles fabricated by the electrical wire explosion technique, deposited on a porous silicon as an active substrate for surface-enhanced Raman scattering (SERS)

This study aims to improve the surface-enhanced Raman scattering (SERS) using gold nanoparticles prepared by the wire explosion technique and deposited on an etched silicon substrate. This spectral technique is highly dependent upon physicochemical properties of the substrate material, to detect very low concentrations of the toxic materials. The morphological and structural features of the prepared gold nanoparticles (AuNPs) have been investigated by the field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The FE-SEM images illustrated that the deposited AuNPs have a non-uniform spherical shape with a rough surface and there were nanogaps between them acting as hotspots at the surface. While the X-ray diffraction pattern indicated the existence of the (111) plane which confirmed the crystalline nature of the AuNPs. Rh6G dye was used as a probe material to examine the performance of these nanoparticles as a SERS substrate. The Raman scattering spectrum of the rhodamine RH6G dye enhanced greatly due to the existence of these nanoparticles, where the enhancement factor (EF) was 2.23×106 when using a deposited AuNPs of concentration 13.46 ppm which is equal to 3×10-5 M, and a reasonable detection limit for a low dye concentration of 10-14M.