Application of silver nanostructures deposited on silicon in SERS for detection of pyridine

The surface-enhanced Raman scattering (SERS) active substrates with high enhancement factor are required to detect trace concentration of biological or organic molecules by using SERS techniques. This work presents the results of the detection of trace concentration of pyridine by using silver nanotrees (AgNTs) that were deposited on silicon. The different densities of AgNTs were fabricated by electroless deposition on silicon wafer by using aqueous solution of HF and AgNO3 with changing etching time. It was observed that with increasing the time of etching the density of the fabricated AgNTs increased at room temperature. The morphology of the fabricated AgNTs was studied by using field emission scanning electron microscope (FESEM). The AgNTs with high branching gave the highest Raman spectrum of pyridine. In addition, the optical properties of the fabricated AgNTs at various etching time have been investigated by using a UV-vis-NIR spectrophotometer. The absorption increased with increasing the etching time due to increasing of branches of silver on silicon substrate.