Silver particles embedded in silicon: The fabrication process and their application in surface enhanced Raman scattering (SERS)

The formation of hybrid structures for creating sensitive sensors is a difficult task. In this study, we developed a facile technique of semiconductor technology to fabricate hybrid structures based on SiO2/embedded Ag/Si and embedded Ag/Si for a surface-enhanced Raman scattering. Herein, our hybrid structures were created in one technological cycle, which consists of the reduction of silver nitrate salt from a solution on the silicon surface and subsequent high-temperature annealing at 1000 degrees C. In addition, it allows not only to preserve the plasmonic properties of Ag particles on the Si surface but also to protect them from further external influences by coating them with a SiO2 layer. Also, the basis for creating such hybrid structures is the performed numerical calculations of the position of a localized surface plasmon resonance as a function of the geometry of structures. Furthermore, the theoretical full-wave electromagnetic modeling of Raman scattering in an embedded Ag/Si structure showed the presence of enhancement regions "hot spots" at sharp corners with a maximum enhancement factor of 106. Finally, surface-enhanced Raman scattering spectroscopy of such structures showed reliable detection of the methyl orange from an aqueous solution at a concentration of 10-5 M.