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Surface-enhanced Raman scattering is a powerful method used in chemoand biosensorics. The aim of this work was to determine the relationship between the signal of Surface-enhanced Raman scattering and the shape of silver nanostructures under the influence of laser radiation with different power.Plasmonic nanostructures were synthesized in silicon dioxide pores on monocrystalline silicon n-type substrate. The pores were formed using ion-track technology and selective chemical etching. Silver deposition was carried out by galvanic displacement method. Synthesis time was chosen as a parameter that allows controlling the shape of a silver deposit in the pores of silicon dioxide on the surface of single-crystal n-silicon during electrodeless deposition. Deposition time directly effects on the shape of metal nanostructures.Analysis of the dynamics of changing the morphology of the metal deposit showed that as the deposition time increases, the metal evolves from individual metallic crystallites within the pores at a short deposition time to dendritic-like nanostructures at a long time. The dependence of the intensity of Surface-enhanced Raman scattering spectra on the shape of the silver deposit is studied at the powers of a green laser (λ = 532 nm) from 2.5 μW to 150 μW on the model dye analyte Rodamin 6G. The optimum shape of the silver deposit and laser power is analyzed from this point of view design of active surfaces for Surface-enhanced Raman scattering with nondestructive control of small concentrations of substances.The silver nanostructures obtained in porous template SiO2 on n-type silicon substrate could be used as plasmon-active surfaces for nondestructive investigations of substances with low concentrations at low laser powers.

Titanium dioxide nanostructures are formed by a simple one-stage method of thermal oxidation of titanium in the temperature range of 700 - 900 °C. The structures were studied by high-resolution electron microscopy and X-ray diffraction. It is shown that, depending on the temperature, nanostructures in the form of crystallites, granules, and dendrites of TiO2-rutile are formed on the surface of metallic titanium. The proposed method is promising for the large-scale creation of advanced functionalized TiO2 surfaces applicable in catalysis and sensorics.

Today, the possibility of amplifying the signal of Raman scattering is intensively studied in order to realize a simple and reliable tool for monitoring of ultra-small concentrations of chemical and biological substances. Plasmon-active nanostructures can serve as the basic element of substrates for signal amplifying, and the degree of amplification is determined by nanostructures size and shape. The formation of nanostructures with a predetermined morphology requires the development of new approaches. In this concern, the paper considers a complex approach of plasmon-active silver nanostructures with a wide range of shapes and sizes formation in the pores of ion-track Sio2templates on silicon. The peculiarities of SiO2templates creation are considered and the etching rates, uniquely determining the parameters of the pores as a function of the etching time, are established. The features of the silver nanostructures formation in the pores of the SiO2template are described for various pore sizes and synthesis regimes (time and solution temperature). The possibility of formation of nanostructures with different shapes as well as evolution of their morphology with variation of synthesis parameters is shown. on the example of dendrites, having a high potential for practical application for amplification of the Raman scattering signal, the possibility of recording Raman spectra was demonstrated using the model analyzer Nile Blue at the concentration of 10-6M/l. The results indicate that plasmon-active silver nanostructures in the pores of ion-track Si02template on silicon can be used as basic element of biosensors to studying ultra-low doses of chemical and biological substances.Communicated by Corresponding Member Valery M. Fedosyuk