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The structure of multi-walled carbon nanotubes exposed to a pulsed high-power ion beam is investigated using the methods of Raman spectroscopy and transmission electron microscopy. It has been shown that irradiation with an ion beam generates significant defects in the structure of nanotubes. With an increase in the number of pulses, processes associated with the annealing of defects in the internal structure of the samples are observed. Electron microscopy data make it possible to distinguish two types of defects leading to a decrease in the interlayer distance of the carbon nanotube wall.

The features of pore formation during photoanodization in electrolytes based on ammonium fluoride are studied depending on illumination, pH, current density. When comparing electrolytes with different pH (acidic and alkaline), a decrease in the pore diameter is observed at the same illumination and current densities in alkaline HF: NH4 OH solutions at a relatively equal etching rate in depth. In dilute HF: NH4 OH: H2 O under low illumination, there is a direct dissolution of silicon with the formation of a «starlike» pore morphology and a branching tendency. In the case of a concentrated solution of HF: NH4 OH 1: 4 branching is observed with increasing current density.

Nanocomposite structures are obtained on multi-walled carbon nanotubes pre-functionalized with argon ions and nonstoichiometric titanium oxide supported by magnetron deposition (MWCNT/TiOx). The morphology of the ensembles of individual MWCNT/TiOx composite nanostructures functionalized with argon ions and the gas response of these nanostructures to NO2 and H2 S are studied. Irradiation of MWCNT layers leads to an increase in their resistance by a factor of 1.5. A change in the resistance of a MWCNT/TiOx nanocomposite upon gas adsorption repeats a similar change in the resistance of an ensemble of irradiated MWCNT, which demonstrate gas-sensitive properties characteristic of a material with p-type conductivity — a decrease in resistance during exposure in an oxidizing gas and an increase in resistance in a reducing gas.

The paper is devoted to the study of the effect of oxygen as an impurity substitution defect in single-layer and double-layer graphene planes on the electronic properties of these structures. The van der Waals interaction is studied for the electronic properties of paired graphene planes of the substitution type for an impurity oxygen atom. Calculations of the «ab initio» electronic zone structure of the studied objects are made. The results obtained are applicable to the analysis of the zone structure of multi-wall carbon tubes containing defects.

Adding an oxidizing agent to a solution of hydrofluoric acid significantly changes the process of electrochemical etching, because allows to accelerate the dissolution of electron silicon. In this work, we studied the formation process and morphology of macropores in high-resistance n-Si depending on the concentration of HCl in the HF: C2 H5 OH electrolyte. It is shown that the presence of HCl leads to a more uniform pore diameter distribution both at the surface and in the layer depth, and the increase in etching rate. With an increase in HCl concentration, a narrower pore diameter distribution is observed; the main pores near the surface approximate in size to the pores in the depth of the porous layer. The results are explained by the action of HCl as an oxidant.

The composites based on manganese oxide (MnO2–х), copper oxide (CuO) and yttrium oxide (Y2 O3) are obtained. The gas response and selectivity of multicomponent composites to toxic and hazardous gases are found. Enhanced gas response of MnO2–х/CuO composite to hydrogen sulfide and methylcyan are observed as compared with as-grown manganese oxide. Doping of MnO2–x by yttrium oxide instead of copper oxide leads to changes gas-sensing properties of the composite to hydrogen sulfide, formaldehyde and sulfur dioxide. The presence of copper and yttrium oxides in MnO2–x increases the response to ethyl alcohol vapors.

Using the methods of scanning force microscopy, the gas sensitivity properties of individual composite nanostructures based on CNTs, functionalized by argon ions and coated with tin and titanium oxides are investigated. The Fermi level shift and the change in longitudinal conductivity upon absorption ammonia and nitrogen dioxide are determined. It is shown that the change in conductivity of the composite nanostructures to the correlates with the Fermi level shift under gases exposure as a result of charge carriers concentration changing in the metal oxide surface layers upon adsorption of gas molecules.

The work is devoted to the study of the influence of the Van der Waals interaction on the electronic properties of the distance of paired graphene planes. Calculations are made of the «ab initio» the width of the band gap as a function of the van der Waals interaction, which is varied by shifting one plane relative to the other. The conditions for the formation of a forbidden band in the band structure of coupled graphene planes with the help of Van der Waals interaction are investigated. The results obtained are applicable for the analysis of the band structure of multi-walled carbon tubes containing defects.

A method for obtaining structures for integrated membranes based on channel silicon is proposed. In this work features of the formation of through channels in electronic silicon are considered depending on the composition of the electrolyte, the concentration of charge carriers and anode etching regimes. It is shown that porous structures in the form of «bottlenecks» are formed under the used regimes. It has been established that in the electrolyte based on HF: C3 H7 OH, to obtain porous layers with a thickness of more than 100 μm, it is necessary to interrupt the anodic etching process, which is due to the feature of pore formation. For the electrolyte based on HF: (CH3 )2CO, the duration of etching may be longer, which is associated with a higher solubility of hydrogen in acetone than isopropanol. The average pore diameter in this electrolyte grows more slowly with depth compared to the use of the HF: C3 H7 OH electrolyte. This effect can be explained by facilitating diffusion in the structures of not only hydrogen but also fluoride ions.