O. A. Ageev

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

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Publications (33)34.53 Total impact

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    ABSTRACT: The kinetic Monte Carlo simulation of GaAs/GaAs(001) molecular beam epitaxial growth considering V/III flux ratio influence on nucleating island characteristics is presented. It is shown that the island density increases with the surface coverage increase and reaches saturation after deposition of ~0.1 monolayer of GaAs. The increase of V/III flux ratio from 3 to 40 leads to the increase of the island density from 1.9-1012 to 2.6-1012 cm-2. At the same time the average size decreases from 4.4 to 4.1 nm. The island size distribution function narrows with V/III flux ratio increase. This is attributed to the shortage of gallium atoms in comparison with deposited arsenic molecules that prevents large island formation and leads to the dramatic growth of little island concentration. The simulation demonstrates good agreement with experimental results.
    No preview · Article · Feb 2016 · Journal of Physics Conference Series
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    ABSTRACT: The results of experimental researches of the geometrical parameters of vertically aligned carbon nanotubes (VACNTs) are present by atomic force microscopy. The analysis of the applicability of the different AFM modes to determine the geometrical parameters of VACNTs array was carried out and based on this analysis the rapid-technique for determination of the length of the nanotubes in VACNTs array was developed. Unified two-layer polysilicon surface micromachining process for manufacture of biaxial micromechanical gyroscope , triaxial micromechanical accelerometer and biaxial nanomechanical accelerometer was proposed. Polysilicon inertial masses were fabricated by optical lithography, dry etching under different masks and wet etching of sacrificial layer. We developed AFM-technique for determination of electrical parameters GaAs nanowires (NWs) , which does not require additional operations of NW fixation and allows one to estimate the resistivity and conductivity type of NW material. The obtained results can use to develop of the nanodiagnostic methods and the processes of formation of micro- and nanoelectronic elements based.
    No preview · Chapter · Jan 2016
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    ABSTRACT: The results of an experimental study of the modification of probes for critical-dimension atomicforce microscopy (CD-AFM) by the deposition of carbon nanotubes (CNTs) to improve the accuracy with which the surface roughness of vertical walls is determined in submicrometer structures are presented. Methods of the deposition of an individual CNT onto the tip of an AFM probe via mechanical and electrostatic interaction between the probe and an array of vertically aligned carbon nanotubes (VACNTs) are studied. It is shown that, when the distance between the AFM tip and a VACNT array is 1 nm and the applied voltage is within the range 20–30 V, an individual carbon nanotube is deposited onto the tip. On the basis of the results obtained in the study, a probe with a carbon nanotube on its tip (CNT probe) with a radius of 7 nm and an aspect ratio of 1:15 is formed. Analysis of the CNT probe demonstrates that its use improves the resolution and accuracy of AFM measurements, compared with the commercial probe, and also makes it possible to determine the roughness of the vertical walls of high-aspect structures by CD-AFM. The results obtained can be used to develop technological processes for the fabrication and reconditioning of special AFM probes, including those for CD-AFM, and procedures for the interoperational express monitoring of technological process parameters in the manufacturing of elements for micro- and nanoelectronics and micro- and nanosystem engineering.
    No preview · Article · Dec 2015 · Semiconductors
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    ABSTRACT: The properties of a point field-emission cathode representing a structure in the form of a silicon carbide tip coated with a thin graphene film are assessed. For the point cathode with the graphene coating, the current–voltage characteristics are constructed in the Fowler–Nordheim coordinates; the work functions φ of the point cathode are calculated by their slope. The possibility of forming heavily doped n +-SiC on the point surface by the sublimation of low-threshold field emission cathodes with low threshold electric fields and field-emission currents is shown.
    No preview · Article · Sep 2015 · Semiconductors
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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.
    No preview · Article · Jul 2015 · Microelectronics Reliability
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    Full-text · Conference Paper · May 2015
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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.
    Full-text · Article · May 2015 · Technical Physics

  • No preview · Article · Apr 2015
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    Full-text · Dataset · Mar 2015
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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.
    Full-text · Article · Mar 2015
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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.
    Full-text · Article · Mar 2015 · Nanotechnologies in Russia
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    ABSTRACT: Techniques are developed to determine the resistance per unit length and the electrical resistivity of vertically aligned carbon nanotubes (VA CNTs) using atomic force microscopy (AFM) and scanning tun�neling microscopy (STM). These techniques are used to study the resistance of VA CNTs. The resistance of an individual VA CNT calculated with the AFM�based technique is shown to be higher than the resistance of VA CNTs determined by the STM�based technique by a factor of 200, which is related to the influence of the resistance of the contact of an AFM probe to VA CNTs. The resistance per unit length and the electrical resis�tivity of an individual VA CNT 118 ± 39 nm in diameter and 2.23 ± 0.37 μm in height that are determined by the STM�based technique are 19.28 ± 3.08 kΩ/μm and 8.32 ± 3.18 × 10–4 Ω m, respectively. The STM �based technique developed to determine the resistance per unit length and the electrical resistivity of VA CNTs can be used to diagnose the electrical parameters of VA CNTs and to create VA CNT�based nanoelectronic elements.
    Full-text · Article · Sep 2014 · Technical Physics
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    ABSTRACT: The influence of the parameters of the deposition process on the stoichiometric composition and electrical and optical properties of ZnO films deposited by the ion-beam sputtering of a ZnO target is studied. It is established that, upon sputtering of a ZnO target with stoichiometric composition, there is a deficit of oxygen in the films deposited. Even for the case of target sputtering in a pure O2 atmosphere, the stoichiometry index of the films is no higher than 0.98. A decrease in the oxygen content in the films is accompanied by a sharp decrease in the resistivity to 35–40 Ω m, narrowing of the optical band gap, and a shift of the optical transmittance edge from 389 to 404 nm. All of the variations in the optical and electrical properties of the ZnO films can be attributed to variations in the concentration and mobility of free charge carriers in the films.
    Full-text · Article · Sep 2014 · Semiconductors
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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.
    No preview · Article · May 2014 · Composites Science and Technology
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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.
    No preview · Article · Mar 2014 · Nanotechnologies in Russia
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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.
    No preview · Article · Jan 2014 · Nanotechnologies in Russia
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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.
    No preview · Article · Jan 2014 · Nanotechnologies in Russia
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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.
    Full-text · Article · Nov 2013 · Technical Physics
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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.
    No preview · Article · Nov 2013 · Carbon
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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.
    Full-text · Article · Feb 2013 · Nanotechnologies in Russia

Publication Stats

98 Citations
34.53 Total Impact Points

Institutions

  • 2009-2015
    • Southern Federal University
      • • Department of Micro- and Nanoelectronics
      • • Department of Chemistry
      • • Institute of Physical and Organic Chemistry
      Rostov-on-Don, Rostov, Russia
  • 2012
    • Taganrog State Pedagogical Institute A.P. Chekhov
      Taganrog, Rostov, Russia