Investigation of silver decorated silicon nanowires as ultrasensitive and cost-effective surface-enhanced Raman substrate

Quantitative analysis of organic pollutants in water and soil is an important issue for the ecological environment and human health. Surface-enhanced Raman spectroscopy (SERS) is a powerful detection technique. Silicon nanostructures are getting more attention due to low-cost fabrication and high enhancement factors for SERS. To detect organic pollutants, silicon nanowires (SiNWs) are fabricated here by metal-assisted chemical etching and silver nanoparticles are deposited by the electroless method. As the length of SiNWs is increased, the enhancement of SERS is decreased. In this work, a systematic study is conducted to discriminate closely related molecules in the tertiary mixture. When the mixture of Rhodamine 6G, Malachite green and Methylene blue) solutions are taken in the ratio (1:1:1), mostly Rhodamine 6G dye is detected in the Raman spectra. When this ratio is changed to (1:2:2), Raman modes of all other dyes are distinguished easily. It emphasizes the importance of research in the area of separation and detection of organic dyes with the help of SERS.