Mechanisms of the Anisotropy Formation of Thermoelectric and Thermomagnetic Phenomena in the Multivalley Semiconductors
Institute for Nuclear Research, NAS of Ukraine, Avenue Nauku, 47, Kyiv, 03680, Ukraine, е-mail: email@example.com
In this review the mechanisms of the formation and the methods to detect the macroscopic anisotropy of properties of multivalley semiconductors with cubic symmetry under the directed external influences (uniaxial elastic deformation, magnetic (non-quantizing) fields of arbitrary intensity) were analysed in details. The connection between the non-diagonal components of the tensor of thermoelectromotive was established both for n-Si and for n-Ge, as well as the reasons that lead in the case of multivalley semiconductors (even at small scattering anisotropy) to the switching effect (typical for the non-diagonal components) were found.
Keywords: germanium, silicon, theory of anisotropic scattering, thermoelectric phenomena, thermomagnetic phenomena.
L.V. Baziuk, H.A. Sirenko
Thermophysical Properties of Metals and Polymer Compositions (Review)
Vasyl Stefanyk’ Precarpathian National University, 57, Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine
The dependence of enthalpy change, coefficient of thermal conductivity, coefficient of thermal capacity, linear coefficient of thermal expansion from temperature, serial number and radius of atom of metals has been analyzed and proved by correlation and regression analysis. Experimental investigation of thermophysical properties of composite polymeric materials based on polytetrafluorineetylene, aromatic polyamide and polyimide and fillers are explored.
Keywords: metals, polymers, polytetrafluoroethylene, aromatic polyamide, polyimide, thermophysical properties, enthalpy, coefficient of thermal conductivity, coefficient of thermal capacity, linear coefficient of thermal expansion, temperature, correlation analysis, regression analysis.
O.M. Makhanets, V.I. Gutsul, N.R. Tsiupak
Influence of Magnetic Field on Electron Energy Spectrum in Complicated Cylindrical Semiconductor Nanotube
Chernivtsi National University, 58012 Kotsiubynsky Str., 2, Chernivtsi, Ukraine, e-mail:firstname.lastname@example.org
The theory of energy spectrum and wave functions of electron in complicated cylindrical semiconductor ( ) nanotube placed into the outer homogeneous magnetic field is established within the approximation of effective masses and rectangular potentials. The dependences of energy spectrum on geometrical characteristics of nanotube and on the magnitude of magnetic field induction are investigated.
V.I. Boichuk, I.V. Bilynskyi, R.Ya. Leshko, L.M. Turyanska
Optical Properties of a Spherical Quantum Dot with Two Neutral Impurities
Ivan Franko Drohobych State Pedagogical University, Institute of Physics, Mathematics and Computer Science, Department of Theoretical Physics, 3 Stryiska St., Drohobych, Lviv Region, 82100, e-mail:email@example.com
Two neutral impurities in the QD have been studied in this work. The singlet and triplet states have been obtained. The influence of the relative position of impurities on the energy spectrum of the system and on the light absorption coefficient has been analyzed.
Keywords: impurity, light absorption coefficient, singlet and triplet states.
A. Groza1, P. Litovchenko1, L. Matveeva2, P. Nelyuba2, M. Pinkovska1, M. Starchyk1
Ineluence of the Neutron Irradiation and Thermal Treatment on the Effect Self-Organization Appearance, Franz-Keldysh and Quantum-Confinement Effects in Monocrystalline Silicon
1Institute of Nuclear Research of the National Academy of Sciences of Ukraine, Prospect Nauky 47, Kyiv 03028, Ukraine
2V. Lashkarev Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Prospect Nauky 45, Kyiv 03028, Ukraine; e-mail:firstname.lastname@example.org
The method of modulation spectroscopy of light electroreflectance (ER) in the spectral range 3…3,8 eV was used in order to study optical and electronic properties, and also inner mechanical stresses of oxygen reach (8•1017 cm-3) silicon, irradiated with fast neutrons (1015…1018 n/cm2), annealed isothermally at 800 oC and chemically etched. The conditions of appearing of the Franz-Keldysh, the quantum-confinement and the surface gettering effects were established. From the analysis of ER spectra, the following parameters were obtained: the energy of electron transition (bandgap), the broadening parameter, the energy relaxation time of charge carriers, the intrinsic mechanical stresses, the electrooptical energy, the surface built-in electrical field, the energy of quantized levels and the quantum well width in dependence on the samples treatment conditions. In samples, irradiated by 1018n/cm2, the splitting of electroreflectance signal was discovered with maxima shifts in opposite sides in comparison with the Еg value for initial sample. The revealed high dose effect is caused by the self-organization of own radiation-induced defects owing to existence of two types separated disorder regions (vacancies and interstitials) with the mechanical stresses of different sings. The carries transport mechanism and the energy-band structure features have been discussed.
Keywords: silicon, neutron irradiation, thermal treatment, electroreflectance, surface gettering, self-organization.
D.M. Freik1,2, T.O. Parashchuk1,2, V.M. Chobanyuk1
Thermodynamics Parameters of Sphalerite Crystal of Zinc Chalcogenides: Quantum-Chemical Calculation
Physical-Chemical institute, Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., 76018, Ivano-Frankivsk, Ukraine, E-mail:email@example.com
Cluster models for zinc sulphide crystal in cubic phase have been constructed. Based on the results of ab initio quantum chemical calculations of the crystal structure of molecular clusters have been defined temperature dependence of the energy and enthalpy of formation, Gibbs potential, specific heats at constant pressure and volume, entropy.
Keywords: cluster model, quantum chemistry, zinc sulfide, thermodynamic parameters.
D.M. Zayachuk, О.S. Ilyina
The Problem of Segregation of Rare-Earth Impurities in Iv-Vi Semiconductors Grown from Doped Melts
Lviv Polytechnic National University, 12 S. Bandera St, Lviv, Ukraine, 79013
The results of non-monotonic distribution of impurities of rare-earth elements (REE) in IV-VI crystals grown from the melt by Bridgman method and doped during growth are analyzed. The analysis is performed in linear and square approaches of dependence of liquidus temperature TL and solidus temperature TS of the system "IV-VI-host - REE impurity" on impurity content x for low concentration of dopant. It is shown that nonlinearity of TL(x) and TS(x) dependences significantly modifies the distribution of impurity along the doped crystals. However for physically reasonable dependences of the liquidus and solidus temperatures on impurity concentration this nonlinearity cannot lead to non-monotonic impurity distribution. It is concluded that non-monotonic dependence like maximum on coordinate distribution of concentration of REE impurity in the IV-VI doped crystals are not caused by a state diagram "IV-VI-host - REE impurity" but are of technological origin. It is suggested that non-monotonous concentration distribution of REE impurities along doped IV-VI crystals is caused by formation of complexes of both dopant and background impurities in the crystal, first of all the complexes of REE impuriries and oxygen, which is always present in the grown process of PbTe crystals from melt.
Keywords: doping, IV-VI semiconductors, Bridgman method, rare-earth impurities, segregation.
V.A. Romaka 1,2, P. Rogl3, Yu.V. Stadnyk 4, L.P. Romaka4,
E.K. Hlil5, V.Ya. Krayovskii2, A.M. Horyn4, O.I. Lakh6
Discovering the Mechanism of Structural Defects Formation of Donor Nature in n-ZrNiSn Intermetallic Semiconductor
1Ya. Pidstryhach Institute for Applied Problems of Mechanics and Mathematics, NAS of Ukraine, Naukova str., 3-b, 79060, Lviv, Ukraine;
2National University “Lvivska Politechnika”, St. Bandera str., 12, 79013, Lviv, Ukraine , е-mail: firstname.lastname@example.org;
3Institut für Physikalische Chemie, Universität Wien, A-1090 Wien, Austria;
4Ivan Franko National University of Lviv, Kyryla and Mefodiya Str. 6, 79005 Lviv, Ukraine;
5Institut Néel, CNRS, BP 166, 38042 Grenoble Cedex 9, France;
6V.I. Lakh NVO “Termoprylad”, Naukova str., 3, 79060, Lviv, Ukraine
The crystal structure, electron density distribution, energy state, electrokinetic and magnetic properties of n-ZrNiSn intermetallic semiconductor, heavily doped by Ni, were investigated. The effect of the accumulation of excess Ni1+x atoms in tetrahedral vacancies of the semiconductor crystal structure, as well as the donor nature of these structural defects, which change the properties of the semiconductor, were established.
Keywords: crystal and electronic structures, semiconductor, conduction.
V.M. Rubish1, V.M. Marjan1, V.O. Stefanovich2, T.I. Yasinko1, M.Yu. Rigan1, O.G. Guranich1, V.V. Tovt2, P.P. Shtets1
Formation Mechanism and Nature of Crystalline Inclusions in the Matrix of Sb2S3–AsSI System Glasses
1Uzhgorod Scientific-Technological Center of the Institute for Information Recording, NASU, 4 Zamkovi Skody Str., Uzhgorod,88000, Ukraine, e-mail:email@example.com
2Uzhgorod National University, 46 Pidgirna Str., Uzhgorod, 88000, Ukraine
Structure and structural changes under isothermal annealing of (Sb2S3)100-x(AsSI)x glasses were investigated by the Raman spectroscopy and X-ray diffraction methods. Nanoheterogeneous structure of glasses is revealed. The phase structure arising in the matrix of glasses during crystallization corresponds to the structure of crystalline SbSI. The sizes of antimony sulfoiodide crystalline inclusions depend on the annealing regime.
B.I. Ilkiv1, S.S. Petrovska1, О.О. Foya1, О.Yu. Khyzhun1,
M.M. Pereginiak2, Ya.V. Zaulychnyy1,2
Interaction of Aerosil Nanoparticles with High-Porous Carbon Materials Obtained Due to Burn-off. ІІ. Change of Energy Distribution of Valence Electrons of Nanosilica and Activated Carbon Due To Mechanochemical Treatment
1Frantsevich Institute for Problems of Materials Science of NASU, 3, Krzhyzhanіvsky Str., Kyiv, 03680, Ukraine, +38-044-424-33-64, e–mail: firstname.lastname@example.org
2National Technical University of Ukraine “Kyiv Polytechnic Institute” Engineering-physical faculty, 35 Politekchnichna Str., Kyiv 03056, Ukraine, +38-044-406-83-70
Effect of mechanochemical activation on the electronic structure of components of nanosilica and activated carbon mixture was investigated by the ultrasoft X-ray emission spectroscopy method. Binding energy of C1s, O1s та Si2p-electrons was studied by the X-ray photoelectron spectroscopy method for the purpose of revealing of chemical bonds formation between component atoms of mixture due to mechanochemical activation. It was found d that bonds between atoms in deep enough nearsurface layers form according to scheme Si-C-O in result of mechanochemical activation of nanosilica and activated carbon mixture.
D.M. Freik, B.S. Dzundza Ya.S. Javorskiy, L.Yo. Mezhylovska
Influence of Scattering Surface on the Boundaries Intergrain Carriers in Vapor-Phase Condensates Solid Solutions PbTe-Sb2 (Bi2) Te3
Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, e-mail:email@example.com
The investigation of surface intergrain limits on scattering of charge carriers in the films of solid solutions based on lead telluride deposited on substrates sital on their thickness. Found that the dominant role played by scattering on the surface and within intergrain, the relative contribution is determined by the type of impurities in the solid solutions PbTe-Sb2 (Bi2) Te3.
Keywords: Lead Telluride, scattering, motility, surface.
N.L. Dmitruk, O.Yu. Borkovskaya, I.B. Mamontova, S.V. Mamykin,
S.Z. Malynych, V.R. Romanyuk
Photocurrent of the Surface-Barrier Structures with Ag Nanopaticles Overlayer on Textured Interface
V.E. Lashkaryov Institute for Semiconductors Physics NAS of Ukraine, 45 Nauky ave., Kyiv 03028, Ukraine, firstname.lastname@example.org
The possibilities of joint effect of texturing interface for Au/GaAs surface-barrier structures and of the surface plasmon excitation in silver nanoparticles deposited on it to decrease the optical losses and to enhance the photocurrent, respectively, have been investigated. The interface microrelief of quasigrating type was fabricated by chemical anisotropic etching of (100) GaAs surface. Silver nanoparticles were deposited after modification of GaAs surface with poly(vinilpyridine). The analysis of the photoelectric and optical characteristics of structures allowed to determine the mechanisms of the light transmittance into semiconductor through the semitransparent Au layer and the surface with Ag nanoparticles. The introduction of the Ag nanoparticles was shown to enhance the photocurrent in addition to texturing effect. The joint effect of the structure efficiency enhancement at AM0 simulated illumination was (2.2 times with respect to the flat structure.
Keywords: surface-barrier structures, silver nanoparticles, texturing interface, photoelectric characteristics, surface plasmon
O.M. Bordun, V.G. Bihday, I.Yo. Kukharskyy
Edge Absorption of Thin Films ZnGa2O4
Ivan Franko Lviv National University, 50, Dragomanov Str., Lviv, 79005, Ukraine, e-mail:email@example.com
Fundamental absorption edge of ZnGa2O4 thin films, obtained by radio-frequency ion-plasmous sputtering, was investigated, using the method of optical spectroscopy. It was ascertained that the optical band gap Eg increases from 4.81 to 4.98 eV after the reduction of annealed films in a hydrogen atmosphere. Consolidated effective mass of free charge carriers in ZnGa2O4 films after annealing and after reduction in hydrogen was estimated. It was found that the concentration of charge carriers after reduction in hydrogen, is 8.16 ( 1018 cm–3, which is typical for degenerated semiconductors. It was shown that the shift of fundamental absorption edge in thin films ZnGa2O4 after reduction in hydrogen is caused by Burstein-Moss effect.
Keywords: thin films, zinc gallate, fundamental absorption edge.
M.V. Potoriy1, P.М. Мilyan2, V.V. Tovt2
Physico-Chemical Interaction In Pseudobinary Systems of Hexachalcohypodiphosphates of Some Metals
1Uzhhorod National University, Department of Chemistry, Uzhgorod, Ukraine
2SRS Physics and Chemistry of Solids, Uzhgorod National University, Uzhgorod, Ukraine
Physico-chemical interaction in Sn2P2S6(Se6)–In4(P2S6(Se6))3, Sn2P2S6(Se6)–Cd2P2S6(Se6), Cd2P2S6–Cd2P2Se6, Sn2(Cd2)P2S6–Zn2P2S6 systems was studied by X-ray phase and differential thermal methods of analysis. Corresponding phase diagrams have been built. It is shown that solid solutions based on Sn2P2S6(Se6) expand the band of application of given materials.
Keywords: phase diagrams, X-ray phase analysis, differential thermal analysis, solid solutions.
О.G. Еrshova, V.D. Dobrovolsky, Yu.М. Solonin
Mechanical Alloys Mg-Me (Me =Al, Ti, Fe): Study Hydrogen Sorption Properties, Thermal Stability and Kinetics of Hydrogen Desorption
Institute for Problems of Materials Science NAS of Ukraine, Krzhyzhanovsky 3, Kiev 03142, Ukraine
Mechanical alloys Mg + 10% wt. Ме (Ме = Al, Ti, Fe) have been derived by the reactive mechanical alloying (RMA) method. Thermal stability of mechanical alloys and kinetic of hydrogen desorption from the alloys have been studied employing thermodesorption at hydrogen pressure of 0.1 MPa. Activation energy of process of hydrogen desorption has been determined. It has been established that Al addition to Mg (without addition of Ti and other metals) does not cause decreasing temperature of the beginning of hydrogen desorption from the MgH2 hydride phase. Absence of positive influence of Al upon thermal stability is explained by the discontinuity of mechanical alloying of MgH2 by Al as a result of formation of more competitive Al3Mg2 compound.
M.A. Zelenko, S.A. Nedilko, K.V. Degtyariova
Conductive Oxide Materials Based on 3d-Metals and Rare Earth Elements
Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska str., 01601 Kyiv, Ukraine, e-mail:firstname.lastname@example.org
This article researches the distinctive features of conductive oxide materials and summarizes their synthesis methods. It investigates the electrical properties of complex oxide materials based on 3d-metals and rare earth elements.
Keywords: conductive oxide ceramics, complex rare earth cuprates, crystal structure, superconductivity.
D.M. Freik, L.V. Turovska, Ya.S. Yavorskiy, V.M. Boychuk, I.M. Andriishyn
Point Defects and Physicochemical Properties of Crystals in Pb-Sb-Te System
Physicochemical Institute, Department of Physics and Chemistry of Solid State at the Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, e-mail:email@example.com
Within crystalquasichemical formalism models of point defects of crystals in the Pb-Sb-Te system were specified. Based on proposed crystalquasichemical formulae of antimony doped crystals PbTe:Sb amphoteric dopant effect was explained. Mechanisms of solid solution formation for РbТе-Sb2Те3: replacement of antimony ions lead sites with the formation of cation vacancies (I) or neutral interstitial tellurium atoms (II) were examined. Dominant point defects in doped crystals PbTe:Sb and РbТе-Sb2Те3 solid solutions based on p-PbTe were defined. Dependences of concentration of dominant point defects, current carriers and Hall concentration on content of dopant compound and the initial deviation from stoichiometry in the basic matrix were calculated.
Keywords: lead telluride, antimony, dopant, solid solution, point defects, crystalquasichemical formulae.
O.V. Kuzyshyn, H.O. Sirenko
Vegetable Oils and Polyglycols as the Base for Liquid Dispersive Systems in Boundary Conditions of the Dynamic Contact
Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine e-mail:firstname.lastname@example.org
The vegetable oils, mineral, naphtene and polyglycol oils, synthetic liquids as lubricating materials for metal surfaces have been considered.
Keywords: vegetable oils, polyglycols, friction, wear, lubricant, naphtene, hydrodynamic effect loading capacity.
G. Ilchuk, V. Kusnezh, R. Petrus’, T. Stanko
The Vapour Thermal Synthesis of CdTe Films from Elementary Components
Department of Physics, Lviv Politechnic National University 12, S. Bandera Str., Lviv, 79013, Ukraine, e-mail:email@example.com
The opportunities for synthesis of cadmium telluride (CdTe) semiconductor films by annealing of the cadmium (Cd) metallic films on glass substrates in the tellurium (Te) vapors were studied. The experiment of annealing-tellurisation (tellurium transfer to the plate with cadmium and expected CdTe synthesis) was preceded by theoretical analysis of partial pressures of the Te vapour above the Tesol, the Cd above the Cdsol, the Te above the CdTesol, the Cd above the CdTesol for the case of congruent sublimation and by the choice of thermal annealing conditions from the results of conducted analysis. With the use of the scanning electronic microscope the surface morphology of the initial Cd films and annealed films were investigated, and quantitative composition was determined from spectra of the characteristic X-ray radiation. Optical properties were investigated.
Keywords: CdTe, II-VI compounds, thin films, vapor pressure.
M.I. Artus1, I.Y. Kostiv1,2
The Reaction Conversion of Surfaces Natural Langbeynite of Sodium Sulfate and Potassium Chloride in Shenite
1Vasyl Stefanyk Precarpathian National University, 57, Shevchenko Str., 76018, Ivano-Frankivsk, Ukraine e-mail:firstname.lastname@example.org
2The State Scientific Research Institute of Gallurgi, 5a, Factory Str., Kalush, Ukraine
Experimental study of reaction conversion of natural Langbeynite of sodium sulfate and potassium chloride in shenite in the temperature range 0 ... 60 °C have been made. According to the result of experimental research the rate constant, reaction order, activation energy and area of the flow process have been found.
Keywords: langbeynite, sodium sulfate, reaction rate constant, activation energy.
D.М. Freik1, Ts.A. Krisko2, І.V. Gorichok1, T.S. Lyba1, L.V. Turovska1,
O.S Krunutcky1, O.M. Matkivsky1, І.P. Jaremij1
Synthesis and Thermoelectric properties Solid Solutions PbTe-Sb2Те3
1Vasyl Stefanyk Prekarpathian University, Shevchenko Str., 57, Ivano-Frankivsk, 76025, Ukraine, e-mail: email@example.com
2Kamyanets-Podilsky State University, Ogienko Str. 61, Kamyanets-Podilsk, 32300, Ukraine, е-mail: firstname.lastname@example.org
The results of the study thermoelectric properties of solid solutions PbTe-Sb2Te3 in the range of 0-5 mol.% Sb2Te3 are presented. Done crystal chemical analysis of defect subsystem of solid solutions on the basis of which done conclusions about possible mechanisms of occurrence of antimony atoms in the crystal lattice.
Research of Physical and Chemical Properties of Glass Depending on Its Composition and The Degree of Processing
Berezhansky Agricultural University, Berzhany, Ukraine
In the glassy state may be substances of different chemical composition with different types of chemical bonds - covalent, ionic, metallic and various physico-chemical properties. Nesylikatne glass in its composition does not contain silicon and boron, phosphorus, beryllium and other elements. This is a relatively new class of polymers designed and obtained by chemists. Recently, due to the intensive development of microelectronics increased interest in the glasses of P2O5-SiO2 and B2O3-SiO2, made the comparison of physical and chemical properties of glass samples.
Keywords: glass, quartz glass, melt, artificial inorganic glass, borate glass, phosphate glass.
F.F. Karimova, S.G. Orlovskaya, M.S. Shkoropado
Study of Refractory Metal Spectral Emissivity During High Temperature Oxidation
Odessa I.I. Mechnikov’s National University, Odessa, Ukraine, Dvoryanskaya str. 2, 65082, 723-62-27, email@example.com
A new method is developed to estimate spectral emissivity of refractory metals during high temperature oxidation. This method is based on combination of optical pyrometry and electrothermography. Spectral emissivity coefficients of oxidized refractory metals filaments are determined.
Keywords: high temperature, oxidation, tungsten, molybdenum, spectral emissivity.
V.I. Mandzyuk1, Yu.O. Kulyk2, N.I. Nagirna3, I.A. Klymyshyn1, I.M. Budzulyak1
The Effect of Thermal Activation of Porous Carbon Materials on Structural and Conductive Parameters
1Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76025, Ukraine
2Ivan Franko National University, 8 Kyrylo and Mefodiy Str., Lviv, 79005, Ukraine
3The Electronic Device College of IFNTUOG’, 223 Vovchynetska Str., Ivano-Frankivsk, 76000, Ukraine
The effect of temperature activation of the porous carbon material (PCM), got by the hydrothermal carbonization method from vegetable raw material at the temperature of 750°C, on its structural and conductive parameters is explored in the article. According to data of small angle X-ray scattering method PCM own the fractal structure formed by mass and superficial fractal, the sizes of which grow at the increase of temperature and time of activation. From the impedance spectroscopy data the thermal activation leads both to reduction (Таct = 300, 400 і 500°С), and increase (Таct = 600°С) of specific conductivity of PCM, that it is conditioned by the changes in the structure of carbon particles, forming on their surface of oxygen functional groups and change of weight content of graphite-like inclusions in the got material.
Keywords: porous carbon material, small angle X-ray scattering, mass and surface fractals, impedance spectroscopy, specific conductivity.
A. Pidluzhna1, I. Grygorchak1, S. Voitovych2
Influence of Grinding and Potassium Nitrite Modification on Thermodynamic and Kinetic Parameters of Li+ Intercalation Current Generation Reaction
1Department for Applied Physics and Nanomaterial Science, Institute for Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University,Kotlyarevsky str. 1, Lviv, 79013 Ukraine
2Department for Biophysics, Informatics and Computers, Ivano-Frankivsk National Medical University, Galytska str 2, 76018 Ivano-Frankivsk, Ukraine Email firstname.lastname@example.org
The natural mineral talc after 30 and 60min of grinding in planetary mill and following potassium nitrite modification were observed in this work. The peculiarities of influence of mechanical activation and chemical modification on structure of talc were determined by X-ray diffraction analysis. Electrodes based on examined materials were prepared and lithium electrochemical cells with metal lithium anode were composed. Discharge and impedance characteristics of composed cells were investigated and parameters of lithium electrochemical intercalation in cathodes based on grinded and modified talc were determined.
Keywords: talc, lithium electrochemical intercalation, impedance spectroscopy
The Influence of Crystallization Over Voltage on Grain Size in the Films of Electrolytic iron Obtained by Pulsed Current
V. Lazaryan Dnepropetrovsk National University of Railway Transport
The paper presents the results of studies of the impact of pulse current electrodeposition of iron structure. A mathematical model to estimate the size of grains of metal in electrolytic films on the value of cathodic overvoltage. Found that increasing the cathodic polarization by regulating the parameters of pulsed current to change the nature of grain growth in electrolytic films from normal to tangential.
S.L. Revo1, М.М. Kuzyshyn2, I.M. Budzulyak2, B.I. Rachiy2, R.P. Lisovskyy2, І.А. Klymyshyn2, К.О. Ivanenko1
NPC-TEG Composite as Electrode Material for Supercapacitors
1Kyiv National Taras Shevchenko University, 64 Volodymyrska Street, Kyiv, 01601, Ukraine, email@example.com 2Vasyl Stefanyk Precarpathian National University,57 Shevchenko Street, Ivano-Frankivsk, 76025, Ukraine
In this paper are presented the results of investigation of structure and properties of nanocomposite material (NCM), which was obtained from nanoporous carbon (NPC) and thermally expanded graphite (TEG), which use as electrode material for supercapacitors (SC) with a double electric layer (DEL). NPC was obtained by hydrothermal carbonization of the material of plant origin . TEG was obtained by thermal expansion of oxidized natural graphite. It was found that the use of TEG reduces internal resistance of SC. Due to this fact, the specific capacitance increases and as determined from electrochemical studies is equal (155 ... 160) F/g. Proposed equivalent electrical circuit which allows modeling of impedance spectra in frequency range (10-3 ... 105) Hz . A physical interpretation of each element of the electrical circuit is given.
Keywords: nanocomposite material, nanoporous carbon, thermally expanded graphite, supercapacitor, specific capacitance.
V.M. Kramar1, P.I. Melnyk2, M.V. Kindrachuk3
Analysis of the Kinetics of the Destruction of the Surface Layers of Friction Pairs Based on Energy Model
1’Yuriy Fedkovych’ Chernivtsi National University, Kotsubinsky Str., 12, Chernivtsi, 58000, Ukraine, e-mail:firstname.lastname@example.org;
2‘Vasyl Stefanyk’ Precarpathian National University, Shevchenko Str., 57, Ivano-Frankivsk, 76025, Ukraine 3National Aviation University, 03680, Kiev, Cosmonaut Komorov Ave. 1, Ukraine.
We investigated the kinetics of destruction of the surface layers by the methods of strength physics and thermodynamics within the limits of the energy model of the wear particle formation in the surface areas of friction pair. The dependence of the wear particle size on the mechanical properties of the material has been established.
F.I. Glazunov, Y.A. Danilenko, G.K. Volkova, V.A. Glasunova, T.E. Konstantinova
Influence of Synthesis Conditions on Structure and Size of Nickel Oxides Nanoparticles
Donetsk Institute for Physics and Engineering named after O.O. Galkin National Academy of Sciences of Ukraine83114, Ukraine Donetsk-114, R.Luxembourg str., 72
Nickel oxide nanopowder of different grain size were obtained by thermal decomposition of nickel oxalate, nitrate and hydroxide. The dependence of morphology and size nanoparticles of nickel oxide from the type of the precursor and its calcination temperature was studied. Formation of nanopowders with 100 % of the cubic phase of nickel oxide with sizes ranging from 5 to 150 nm with a monodisperse or bimodal size distribution and monocrystal or porous structure (depending on the precursor and the calcination temperature) has been shown by transmission electron microscopy and X-ray analysis.
Keywords: nickel oxide, nanopowder, thermal decomposition, nickel hydroxide, nickel oxalate, nickel nitrate, size, structure.
T.M. Bishchanyuk1, R.Ya. Shveth1, І.І. Grygorchak, S.І. Budzulyak2,
L.S. Yablon2, I.A. Klymyshyn3
Thermodynamic and Kinetic Features of The Formation of Current Due to Li+ Intercalation in Supramolecular Ensembles Hierarchical Architecture Based on MCM-41 and Expanded Graphite with Carbamide Kavitand
1Lviv Polytechnic National University, 12, st. S.Bandery, Lviv, 79013, Ukraine? e-mail:Ivangr@rambler.ru
2NASU V.E. Lashkaryov Institute of Semiconductor Physics, 41, pr. Nauki, Kyiv-28, 03028, Ukraine 3Stefanyk Precarpathion National University, 57, Shevchenko Str., Ivano-Frankivsk, 76025, Ukraine
Doublet matrix hierarchical structures of configurations <molecular lattice matrix МСМ-41 and <molecular lattice matrix G were synthesized. Their application in the Li+-process of the intercalated current generation reaction showed essential growth of the Gibbs energy change in the reaction and improvement of the discharge process compared with initial siliceous matrix or expanded graphite.
Keywords: molecular lattice matrix structures, intercalation, Gibbs energy, supramolecular ensembles, molecular recognition.
V.М. Коlomiets, V.B. Loboda, Yu.О. Shkurdoda, V.O. Kravchenko, S.M. Khursenko
Magnetoresistive Properties of Films Co/Cu/Co/S With an Additional Ultra Slim Layer Cr
Sumy State Pedagogical University named after A.S. Makarenko, Romens’ka str., 87, Sumy, 40002, Ukraine
Results of experimental studies of giant magnetoresistance effect in thin films of Co/Cu/Co/Cr/S and Co/Cu/Cr/Co/S with layer thicknesses in the range of dCo = 20 – 50 nm, dCu=2 – 20 nm and dCr = 2 – 20 nm are presented. One can found samples of Co/Cu/Co/Cr/S with layer thicknesses in the range of dCo = 20 – 40 nm, dCu =3 – 15 nm, dCr = 3 – 10 nm is observed the GMR effect with the maximum amplitude (1,8 %) after annealing at temperature 550 K. Anisotropic magnetoresistance is observed for all investigated samples Co/Cu/Cr/Co/S.
Keywords: giant magnetoresistance, spacer, anisotropic magnetoresistance, spin-dependent scattering, impurities, interfaces.
B. K. Ostafiychuk, I. P. Yaremiy, U. O. Tomyn, S. I. Yaremiy
Impact of Anisotropy in Orientation of Radiation Defects on the Value of X-Rays Absorption
Vasyl Stefanyk Precarpathian National University, 57, Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine, e-mail:email@example.com
Anisotropy of the radiation-caused dislocation loops orientation was considered at calculation of X-rays absorbtion. The coefficient depending on the relative spatial orientation of the Burgers vector of the loop and the diffraction vector for a set of loops at different reflection was calculated. Theoretical rocking curves were modeled taking into account mentioned above anisotropy. And it was shown that their intensity outside the additional oscillating structure is significantly different from the intensity of the curves simulated in assumption that the radiation caused dislocation loops occur in all crystallographic planes with the equal probability.
Keywords: anisotropy, extinction coefficient, dislocation loop, Burgers vector.
O.P. Krehel, B.І. Turko, М.R. Panasyuk, V.B. Kapustianyk,
Yu.G. Dubov, G.O. Lubochkova
Photoelectric Properties of ZnO / CuO Heterostructures
Scientific-Technical and Educational Center of Low Temperature Studies, Ivan Franko National University of Lviv 50, Dragomanova Str., Lviv, 79005, Ukraine
n-ZnO/p-CuO heterojunction was obtained by hight frequency magnrtron sputtering method. This was the first investigation of the photosensitivity of such a structure in the wavelength range from 600 to 2000 nm. It was established that the photodiode has a maximum sensitivity at wavelength range 900 – 1100 nm. In addition, revealed a significant sensitivity in the wavelength range 1400 – 1600 nm, which was due to the photodesorption of oxygen from the upper layer of ZnO. A structure prepared on the n-ZnO/p-CuO basis can be used as a photodiode for detecting photons of infrared spectral region.
Keywords: heterojunction, zinc oxide, photovoltaic characteristics.
V.V. Kuryliuk, O.A. Korotchenkov, A.B. Nadtochiy
Strain Relaxation in Si/Ge Heterostructures with Quantum Dots
Faculty of Physics, Taras Shevchenko Kyiv National University, Volodymyrska Str. 64, Kyiv, 01601, E-mail:firstname.lastname@example.org
The influence of a thin SiО2 layer, placed between the Si substrate and Ge quantum dot, on the strain relaxation inside the substrate is computationally investigated employing FEM techniques. Concomitant modifications of the band structure near the interface are also analyzed. Experimental surface distributions of the surface photovoltage signal give a general framework of a spatial distribution of the photogenerated electrons and holes near the interface relevant to the generation of capturing potential caused by the dots.
Keywords: quantum dot, strain, relaxation, photovoltage.
V.M. Katerynchuk1, Z.R. Kudrynskyi1, V.V. Khomyak2,
I.G. Orletsky2, V.V. Netyaga1
Properties of Anisotype n-CdO–p-InSe Heterojunctions
1Frantsevich Institute of Materials Science Problems, National Academy of Sciences of Ukraine, Chernivtsi Branch, I.Vilde str. 5, Chernivtsi, Ukraine 58001; e-mail:email@example.com
2Yuriy Fedkovych Chernivtsi National University, Kotsybynsky str. 2, Chernivtsi, Ukraine 58012
Anisotype n-CdO–p-InSe heterojunctions were created for the first time on the basis of InSe layered crystals. Temperature dependences of I-V characteristics of the heterojunctions were studied. Mechanisms of charge transport through the barrier under forward and reverse bias were established. Photosensitive region of the heterojunctions was defined.
Keywords: heterojunctions, layered crystals, CdO, InSe.
D.V. Korbutyak1, S.V. Tokarev2, S.І. Budzulyak1, A.O. Kuryk1,V.P. Kladko1, Yu.O. Polishchuk1, O.M. Shevchuk2, H.A. Ilсhuk2, V.S. Tokarev2
Optical Properties and Characteristics of Structural Defect in the Nano-Crystals of CdS:Cu and CdS:Zn Synthesized in Polymeric Matrices
1 Institute of semiconductor physics of National Academy of Science of Ukraine, 41, Nauki ave., 03028 Kyiv, Ukraine, firstname.lastname@example.org
2 Lviv Polytechnic National University, 12, Stepana Bandery Str., 79013 Lviv, Ukraine
The technology for synthesis of nano-crystal (NC) of CdS:Cu and CdS:Zn in polymeric matrices was developed.The complex investigations of optical spectra absorption, photoluminescence and X-ray structure analysis of CdS NCwere carried out depending on concentration of the Cu and Zn dopants added within the range of (1 ( 10) %. It was established that Cu dopant concentratedat the surface NC passivatingthe vacancy-type defects which are the superficial emission centers. On the contrary,the zinc dopant penetrated into bulkof CdS NC thus creating the additional superficial defects which are the radiative recombination centers. It is noteworthily that a crystal lattice constant of CdS NC droppeddown from d = 0,585 nm (for the undoped CdS NC) to d = 0,581 nm (for the CdS NCdoped by zinc up to level NZn= 10 %).