Improvement of SERS for detection of ultra-low concentration of methyl orange by nanostructured silicon decorated with Ag nanoparticles

Abstract

We studied the effect of nanostructured silicon integrated with Ag nanoparticles (NPs) on surface enhanced Raman scattering (SERS) to detect methyl orange (MO). Ag NPs are deposites on the two types of porous silicon, single-layer porous silicon (s-PSi) and porous silicon photonic crystals (PSi PhCs). Their characteristics were confirmed by scanning electron microscopy (SEM) and reflectance. SERS activity of the substrates was compared by using MO as the probe molecules. The results with SERS experiments showed that SERS activity of Ag NPs/PSi PhCs was much stronger than that of Ag NPs/s-PSi with 6.8-fold improvement. The limit of detection of MO was 10−9 M and the linear range was from 10−9 to 10-3 M.