M. M. Melnichenko

Electrodynamic properties of the nanocarbon/polymer composites with aligned by magnetic field secondary non-conductive component

Multiwall carbon nanotubes/epoxy and graphite nanoplatelets/epoxy composite materials (2-5 wt %) as well as the composite materials with barium hexaferrite as secondary filler (27 wt %) were prepared. Alignment of barium hexaferrite nanoparticles was performed by magnetic field action during polymerization process. Morphology, the electrical conductivity and shielding efficiency of the composite materials in the frequency range of 36-55.5 GHz were investigated. Optical and electron microscopy, standard 2- and 4-probe methods of electrical conductivity measurement and network analyzer were used for that purpose. The arguments about secondary filler addition and its alignment on electrodynamic properties of the obtained composite materials are given.

Local electronic properties of the surface of the nanostructured silicon layers

Local energy characteristics of nanostructured silicon surface were studied by the tunneling spectroscopy method. Obtained current-voltage characteristics of nanostructured silicon layers, depending on the parameters of the formation of nanostructured silicon, without and under the illumination by ultraviolet radiation on air and in gas environment. Thus there is a different degree of filling of the valence band and the conduction band, a significant difference in the bandgap and the appearance on the curve of tunneling conductance of new peaks in gas environment. The results indicate that the method of scanning tunneling spectroscopy can be used in the field of surface chemistry, nanoelectronics and sensors.

Nanostructured silicon as a multifunctional material for micro- and nanoelectronics

The paper presents technique for single-crystal silicon surface modification by chemical etching. The technique makes it possible to obtain homogeneous nanostructured silicon layers with a thickness 3-60 nm. It was found, that the photosensitivity of such layers depends on their thickness. The method of scanning tunneling spectroscopy showed, that layer thickness changes affect the type (n- or p-) of conductivity. The revealed effect of the conductivity type change could be prospective for practical application of nanostructured silicon in nanoelectronics.

Nanoindentation for surface modification of nanofilms

In the work it is shown practical use of a scanning tunneling microscope for indentation in the continuous micro- and nano-range. A maximum load of 2.64 cN (and 0.4 cN minimum) was applied on a piezo-scanner to achieve the indentation. The relaxation changes of modified surface by contact method was investigated. It is shown that within a few hours of modification there is clear evidence of inevitable loss of information about the morphology of initially modified area. The possibility of modifying the sample surface by tunneling current was shown. This may enable preparation of the surface for subsequent applications in which it is necessary to reduce the average irregularities of the surface. Nano-objects on the surface of the experimental samples were created by using the developed method.

Complex studies of properties of nanostructured silicon

Nanocrystalline silicon layers ( 3-35nm ) have been formed upon single-crystal silicon substrates of very large area (100 cm2), multicrystalline silicon substrates and metallurgical silicon substrates by stain etching. We studied optical and structural properties of nanocrystalline silicon by photoluminescence, reflection, scanning tunnel microscopy, scanning electron microscopy, Auger electronic spectroscopy and SIMS methods. Researches of properties of nc-Si, received by a method of chemical processing, have confirmed an opportunity of creation of this multifunctional material with stable characteristics. The authors have observed the sensors systems with use of nanocrystalline silicon as a sensitive layer, which properties depend on thickness of a received layer and are controlled by parameters of technological process. On an example of the photoluminescent sensor with nc-Si layer it is shown, that such sensor can be successfully used for definition of small concentrations of toxins (pesticides phosalone 10-8-10-9 mol/l ), and also for specific biological pollutant, such as protein components, polysaccharides, cells used during biotechnological synthesis.

Surface modification and creation of nano-objects for nanoelectronics

The practical use of a scanning tunneling microscope for modifying the sample surface and for creation of nano-objects on the sample surface is shown. The possibility of modification of the sample surface by tunneling current was shown. Nano-objects on the surface of the experimental samples were created using contact and non-contact modification of surface. This may also enable preparation of the surface for subsequent applications in which it is necessary to reduce the average irregularities of the surface.

Nano-structured silicon based lab on a chip for diagnostics

The immune biosensor are proposed in the lab on a chip form based on the nano-structured silicon for simultaneous analysis of samples number. The procedure of the nano-structured silicon formation and preparation of the photoresistor-test strips have been described and used in case of the cow retroviral leukemia express diagnostics.

Application of nanostructured silicon to manufacturing of solar cells

In the paper the process of controlled formation of nanostructured silicon is demonstrated and the optical performance compared to standard and textured interfaces. The influence of the formation technique type on its structure, photoluminescent and anti-reflecting properties is studied. The layers of nanostructured silicon have been formed on the textured surface of solar cells. It has been demonstrated that the use of nanostructured silicon reduces the anti-reflection coefficient significantly. It is also shown, that the formation of nanostructured silicon on a textured substrate of singlecrystal silicon after formation on them of contact systems results in decrease of consecutive resistance, increase of short circuit current, decrease of shunting resistance and increase of efficiency.

A new nanostructured silicon biosensor for diagnostics of bovine leucosis

In this report we propose a new instrumental method for the biochemical diagnostics of the bovine leucosis through the registration of the formation of the specific immune complex (antigen-antibody) with the help of biosensor based on the nano-structured silicon. The principle of the measurements is based on the determination of the photosensitivity of the surface. In spite of the existed traditional methods of the biochemical diagnostics of the bovine leucosis the proposed approach may provide the express control of the milk quality as direct on the farm and during the process raw materials. The proposed variant of the biosensor based on the nano-structured silicon may be applied for the determination of the concentration of different substances which may form the specific complex in the result of the bioaffine reactions. A new immune technique based on the nanostructured silicon and intended for the quantitative determination of some toxic substances is offered. The sensitivity of such biosensor allows determining T-2 mycotoxin at the concentration of 10 ng/ml during several minutes.