Abstract. The investigation of porous silicon/silver nanostructured composite layers (PS/Ag) via Raman spectroscopy technique has been carried out. Interpretation of PS/Ag Raman spectra has been proposed. Data from films acquired by varying anodization time showed a significant shift of a Raman peak primarily located at the frequency expected for monocrystalline silicon towards lower energy. In addition to the single peak a number of low-frequency bands emerged in the Raman spectra of silver-functionalised porous silicon. These effects have been interpreted as due to the influence of functionalizing silver nanoparticles and synthesis parameters on the structure and properties of composite material.
IntroductionPorous silicon (PS) and PS-based composite nanostructures are of great interest due to unique properties of such materials including photoluminescence, electroluminescence and the dependence of refraction index on porosity. It is well established that porous silicon is a promising material for a number of applications associated with micro-, nano-and optoelectronics, targeted drug delivery, and gas sensing [1] by virtue of its high specific surface area and extensive capability for surface functionalization. Composite porous silicon -silver materials can also act as a promising substrate for identification and structural characterization of various biological and chemical structures due to the presence of pronounced surface enhanced Raman scattering effect (SERS) [3] caused by collective oscillations in silver nanoparticle electron density. It should be noted that silver-functionalized porous silicon layers can be used in order to implement optical filters for fiber-optic communication systems [2], since the contemporary thin-film filters are expensive due to the necessity of ultra-high vacuum maintaining during the synthesis process.