O. A. Ageev

Southern Federal University, Rostov-on-Don, Rostov, Russia

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Publications (22)29.77 Total impact

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    ABSTRACT: In this work the results of experimental studies of a fabrication of advanced probes for Atomic Force Microscopy (AFM) using Focused Ion Beam (FIB) and nanolithography are reported. Ability to restore the functionality of broken AFM probe tips is shown. The superior performance of FIB-fabricated probes by observing AFM images of the nanostructures is demonstrated. It is shown that the formation of multiprobe AFM cantilevers by FIB-induced deposition of tungsten allows creating an electrical measurement tool for nanotechnology and high-performance instrument for probe nanolithography. It is shown that the use of modified cantilevers for the diagnostics of submicron structures allows one to minimize the artefacts of AFM images, as well as to increase the accuracy of the obtained results.
    Microelectronics Reliability 07/2015; DOI:10.1016/j.microrel.2015.06.079 · 1.43 Impact Factor
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    ABSTRACT: We propose a complex model of local anode oxidation of metals taking into account the processes occurring in the probe–substrate system in dry air, in water vapor, and in the water film adsorbed on the substrate surface. It is shown that local anode oxidation occurs due to generation of oxygen ions as a result of decomposition of water molecules in an electric field; the predominant source of oxidizer is the film of water adsorbed on the substrate surface. The results of numerical simulation of local anode oxidation of titanium demonstrate good correlation with experimental dependences of the height of oxide nanostructures on the duration of local anode oxidation, which confirms the effectiveness of the proposed model. Our results can be used in the development of technological processes of formation of elements of nanoelectronics by local anodic oxidation.
    Technical Physics 05/2015; 60(5):717-723. DOI:10.1134/S1063784215050023 · 0.54 Impact Factor
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    ABSTRACT: The power conversion efficiency of single layer organic solar cells can approach 10% with blends such as the polymer PTB7 and the fullerene derivative PC71BM. Here the detailed structure of PTB7:PC71BM blends deposited with and without addition of diiodooctane is studied by transmission electron microscopy and scanning probe microscopy. The details of bulk structure, such as the thickness of the layer covering fullerene domains and the grain structure of the film are examined. We find that fullerene-rich domains can be near the surface of the film or buried deeper, near the substrate. The local electrical properties of these blends are studied by conductive atomic force microscopy for different configurations of electrodes. Different power conversion efficiencies of blends with and without diiodooctane are explained in terms of local photoconductive properties.
    03/2015; 3(16):-. DOI:10.1039/C5TA01224D
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    ABSTRACT: In this work we present the results of studying the influence of the local anodic oxidation (LAO) technological modes on the process of formation of oxide nanodimensional structures (ONSs) at the surface of Gallium Arsenide epitaxial structures (ESs). We have studied the influence of the amplitude and duration of pulses of voltage applied to the system probe-substrate and amplitude of cantilever vibrations on the geometric parameters of GaAs ONS. The influence of LAO modes on the geometric parameters of profiled nanodimensional structures (PNSs) obtained at the surface of GaAs ES after etching the ONS formed by LAO has been studied. It is established that an increase in the amplitude and duration of pulses of the applied voltage by LAO results in an increase in the height, depth, and diameter of oxide and profiled nanodimensional structures at the surface of GaAs ES. It is shown that an increase in the amplitude of the cantilever vibrations from 3 to 26 nm results in a decrease in the PNS from 9.1 ± 1.6 to 3.4 ± 0.3 nm and diameter of PNS from 274 ± 34 to 167 ± 29 nm. The results may be used for developing the technological processes for preparing an element base for nanoelectronics based on Gallium Arsenide.
    Nanotechnologies in Russia 03/2015; 10(3-4):214-219. DOI:10.1134/S1995078015020032
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    ABSTRACT: Here, we show that a prediction of conductivity in composites can be improved by replacing fitting parameters of the percolation models by information on composite’s microstructure. The methodology was demonstrated on the modified McCullough’s structure-oriented model combined with current maps obtained by Conductive Atomic Force Microscopy (CA-AFM). The approach was tested on nanocomposites with graphene nanoplatelets (GNPs/PS) and proved to be coherent with experimental conductivity measurements and able to predict a percolation threshold. For the composite GNPs/PS both experimental and calculated percolation thresholds are approximately equal to 0.9 wt.% of GNPs. The model can be used for a prediction of conductivity of different kinds of conductive–dielectric composites.
    Composites Science and Technology 05/2014; 95:38–43. DOI:10.1016/j.compscitech.2014.02.006 · 3.63 Impact Factor
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    ABSTRACT: In this work the results obtained in experimental studies of conditions of the nanoscale profiling of a silicon substrate surface under the ion stimulation of W and Pt deposition by a Ga+ ion beam are represented. It is shown that, according to combinations of process conditions, deposition, or etching processes, conditions of the formation of transition structures can also be implemented. It is found that the rate of ionstimulated deposition of W and Pt averages 8 nm/min and 50 nm/min for ion-beam currents of 2.3 pA and 7.9 pA, respectively, and the rate of ion-beam etching of a silicon substrate is 6 nm/min and 55 nm/min for ion-beam currents of 2.3 pA and 111.4 pA respectively. With the use of these results, the modes are determined and a prototype of sensing element of tunnel accelerometer is formed using focused ion beams (FIBs). The results can be used to develop manufacturing methods of generating patterns of nano- and microelectronics and nano- and microsystem engineering on the basis of FIBs.
    Nanotechnologies in Russia 03/2014; 9(3-4):145-150. DOI:10.1134/S1995078014020025
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    ABSTRACT: This paper presents the results of a mathematical model developed for calculating two-dimensional topography of the substrate surface when etching by a focused ion beam (FIB). A simulation of the two-dimensional relief of the substrate when irradiated by the FIB was carried out. An algorithm and software were developed making it possible to forecast the parameters of the surface relief depending on the characteristics of the ion beam and scanning system. The algorithm takes into account the redeposition of the sputtered material. The adequacy of the model is confirmed by a comparison with the results of experimental investigations.
    Nanotechnologies in Russia 01/2014; 9. DOI:10.1134/S1995078014010030
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    ABSTRACT: The results of experimental studies of the resolving power and accuracy of nanosized profiling using focused ion beams (FIBs) are presented. Dependences of the resolving power on the ion beam current were obtained for the boron-doped (10 ohm cm (100)) silicon substrate during FIB etching. It has been established that the best resolution upon silicon etching determined by the average thickness of the etched line is 15–52 nm and corresponds to ion beam currents of 1–30 nA. It has been shown that the precision in the formation of a topological pattern on the substrate surface increases with the decreasing magnitude of the ion beam current in the range of 0.5 pA to 1 nA, and the relative error in the formation of the nanostructure decreases from 5.10 to 0.07. The results of our research can be used to develop manufacturing processes when creating submicron structures and elements of nanoelectronics and nanosystem technology by using FIB.
    Nanotechnologies in Russia 01/2014; 9. DOI:10.1134/S1995078014010029
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    ABSTRACT: We report on the results of experimental study of an array of vertically aligned carbon nanotubes (VA CNTs) by scanning tunnel microscopy (STM). It is shown that upon the application of an external electric field to the STM probe/VA CNT system, individual VA CNTs are combined into bundles whose diameter depends on the radius of the tip of the STM probe. The memristor effect in VA CNTs is detected. For the VA CNT array under investigation, the resistivity ratio in the low- and high-resistance states at a voltage of 180 mV is 28. The results can be used in the development of structures and technological processes for designing nanoelectronics devices based on VA CNT arrays, including elements of ultrahigh-access memory cells for vacuum microelectronics devices.
    Technical Physics 11/2013; 58(12). DOI:10.1134/S1063784213120025 · 0.54 Impact Factor
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    ABSTRACT: The temperature dependence of electrical conductivity of nanocomposites with polystyrene and graphene platelets (GNPs) was studied. It was found that for low loadings of GNPs the conductivity behaviour changed significantly within the temperature range of 295-369 K. Thus, conductivity saw a drop with decrease of temperature from 369 to 331 K. The corresponding curve was approximated by the mechanism of hopping conductivity. Within the temperature range of 331-305 K a slight decrease of conductivity was observed. The latter was well-fitted by exponential curve with coefficients related to fluctuation-induced tunnelling of electrons between neighbour graphene platelets. Within the low-temperature range of 305-295 K a growth of conductivity was explained by increasing of electron tunnelling through the contact caused by the creation of electret state. The latter was presumably formed by polarisation of the polymer between edges of two neighbouring graphene platelets. The observed dependence of conductivity upon temperature is non-linear for low loadings of GNPs and it is close to the linear dependence for higher loadings of the filler.
    Carbon 11/2013; 63:317-323. DOI:10.1016/j.carbon.2013.06.084 · 6.16 Impact Factor
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    ABSTRACT: A technique for determining Young’s modulus of oriented nanowhiskers using atomic force microscopy is developed. Results of studying the effect of geometric parameters on Young’s modulus of oriented gallium arsenide nanowhiskers are presented. Young’s modulus value has been found experimentally for the GaAs nanowhiskers, which varied from 9 to 143 GPa depending on their aspect ratio. It is shown that Young’s modulus of the GaAs nanowhiskers depends on their aspect ratio and can exceed Young’s modulus of the bulk GaAs. The results can be used in the development of technological processes for forming structures of the nano- and microsystem hardware and the nano- and microelectronics based on oriented nanowhiskers, in particular arsenide gallium nanowhiskers, as well as in the development of techniques for the nanodiagnostics of filamentary structures.
    Nanotechnologies in Russia 02/2013; 8(1-2). DOI:10.1134/S1995078013010023
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    ABSTRACT: Results obtained in a study of the influence exerted by the technological modes of local anodic oxidation (LAO) on the process in which nanosized oxide structures (NOSs) are formed on the surface of gallium arsenide are reported. The effect of the amplitude and duration of voltage pulses applied to the probesubstrate system, relative air humidity in the technological chamber, and amplitude of cantilever oscillations on the geometric parameters of gallium arsenide NOSs has been examined. It was found that raising the relative humidity from 60 to 90% results in a decrease in the threshold LAO voltage from 7.0 to 6.0 V. It is shown that raising the oscillation amplitude from 0.1 to 2.8 nm leads to a decrease in the NOS height from 3.20 ± 0.34 to 1.10 ± 0.13 nm and in the NOS diameter from 218.4 ± 29.5 to 78.1 ± 10.3 nm.
    Semiconductors 12/2012; 46(13). DOI:10.1134/S1063782612130027 · 0.71 Impact Factor
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    ABSTRACT: A latex technique is used to prepare graphene/polystyrene and graphene/poly(propylene) composites with varying GR loadings. Their electrical properties and the corresponding volume organisation of GR networks are studied. Percolation thresholds for conduction are found to be about 0.9 and 0.4 wt% for GR/PS and GR/PP with maximum obtained conductivities of 12 and 0.4 S m−1 for GR loadings of 2 wt%, respectively. Investigations using SEM and electrical conductivity measurements show that for the preparation conditions used GR forms an isotropic 3D network in the PS matrix, but GR forms a 2D network in the PP matrix. The different GR network organisations are possibly forced by the different melt flow behaviour of the matrix polymers during processing and the subsequent crystallisation of PP.
    Macromolecular Chemistry and Physics 06/2012; 213(12). DOI:10.1002/macp.201200116 · 2.45 Impact Factor
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    ABSTRACT: The local electrical properties of a conductive graphene/polystyrene (PS) composite sample are studied by scanning probe microscopy (SPM) applying various methods for electrical properties investigation. We show that the conductive graphene network can be separated from electrically isolated graphene sheets (GS) by analyzing the same area with electrostatic force microscopy (EFM) and conductive atomic force microscopy (C-AFM). EFM is able to detect the graphene sheets below the sample surface with the maximal depth of graphene detection up to ≈100 nm for a tip-sample potential difference of 3 V. To evaluate depth sensing capability of EFM, the novel technique based on a combination of SPM and microtomy is utilized. Such a technique provides 3D data of the GS distribution in the polymer matrix with z-resolution on the order of ≈10 nm. Finally, we introduce a new method for data correction for more precise 3D reconstruction, which takes into account the height variations.
    Advanced Functional Materials 03/2012; 22(6). DOI:10.1002/adfm.201101796 · 11.81 Impact Factor
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    ABSTRACT: A technique for determining Young’s modulus of vertically aligned carbon nanotubes using the refined micromechanical model of the nanoindentation of a forest of vertically aligned carbon nanotubes is developed. The results of experimental studies of Young’s modulus determination for vertically aligned carbon nanotubes with different geometrical parameters are given. It is shown that, for a forest of carbon nanotubes with an effective diameter of around 100 nm and an effective length of approximately 2 μm, as well as for a forest with an effective diameter of carbon nanotubes of roughly 52 nm and their effective length of nearly 500 nm, the values of Young’s modulus are 1.68 ± 0.08 and 1.01 ± 0.05 TPa, respectively. Our results can be used for developing the technological processes of the formation of structures for nano- and microelectronics and nano- and microsystem technology on the basis of vertically aligned carbon nanotubes.
    Nanotechnologies in Russia 02/2012; 7(1-2). DOI:10.1134/S1995078012010028
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    ABSTRACT: The paper presents the results of experimental investigations into probe modification for atomic-force microscopy (AFM) and scanning tunneling microscopy (STM) by etching the point of AFM cantilevers and tungsten STM probes by applying the method of focused ion beams (FIBs). It is shown that the use of etching by the IB method allows one to obtain the probes with rounding that is less than 10 nm and with an aspect ratio of 1: 50. The application of these probes increases the resolution and the reliability of measuring by the AFM and STM methods. The obtained results can be used for developing the technological processes of production and modification of sensor probes for AFM and STM, as well as the methods for diagnostics of the structures of microelectronics, nanoelectronics and the microsystem and nanosystem technologies.
    Russian Microelectronics 01/2012; 41(1). DOI:10.1134/S1063739712010052
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    ABSTRACT: The results of experimental studies of modes in which nanosize structures are formed on a silicon substrate by method of focused ion beams are presented. Dependences of the diameter and depth of the nanosize structures on the ion beam current and time of exposure to the ion beam at a point are obtained. It is demonstrated that the main factor determining the rate of ion-beam milling is the ion beam current. The results of the study can be used in the development of technological processes for the fabrication of components for nanoelectronics and nanosystems engineering.
    Semiconductors 12/2011; 45(13). DOI:10.1134/S1063782611130021 · 0.71 Impact Factor
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    ABSTRACT: Experimental results on the conditions of activation of probe nanolithography of a thin titanium film by means of local anodic oxidation are reported. It is established that ultraviolet stimulation reduces the geometric dimensions of nanometric oxide structures. The stimulation is accompanied by an increase in the amplitude and duration of the threshold voltage pulse, correspondingly, from 6 to 7 V and from 50 to 100 ms at the relative humidity 50%. The experimental data on the effect of the cantilever coating material and substrate temperature on the geometric dimensions of nanometric oxide structures are reported.
    Semiconductors 12/2010; 44(13):1703-1708. DOI:10.1134/S1063782610130178 · 0.71 Impact Factor
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    ABSTRACT: Azomethine complexes of copper, nickel, cobalt, and zinc are demonstrated to favor selective transfer in the medium of polyorganosiloxanes. In studies of the friction surfaces with the use of methods of optical and scanning electron microscopy, energy-dispersion electron probe X-ray microanalysis, and infrared frustrated total internal reflection spectroscopy, the formation of a transition-metal and tribopolymer film containing polyorganosiloxane fragments is found. Keywordspolyorganosiloxanes-additives-coordination compounds-azomethines-esters-tribochemical reactions-friction polymers
    Journal of Friction and Wear 10/2010; 31(5):387-397. DOI:10.3103/S1068366610050119 · 0.34 Impact Factor