D.M. Freik, M.A. Lopyanko
Nanostructured Thermoelectric Materials: Challenges, Technologies, Properties (Review)
Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, E-mail:fcss@pu.if.ua
A review the problems of thermoelectricity nanoscale materials. Attention is focused on the specifics of various processes in quantum dimensional structures (quantum wires, dots, wells), technology of their formation. The attention to research areas in order to achieve optimal values of parameters of thermoelectric nanostructures.
Keywords: nanostructures, thermoelectricity, quantum-size effects, nanotechnology.
D.M. Freik1, M.O. Galuschak2, O.S Krunutcky2, O.M. Matkivskiy1
New Nanocomposite Thermoelectric Materials (Review)
1Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, E-mail:fcss@pu.if.ua
2Ivano-Frankivsk National Technical University of Oil and Gas, 15, Carpathian Str.,
Ivano-Frankivsk, 76001, Ukraine
A review works on the problems of obtaining and features promising thermoelectric properties of semiconductor composite materials for thermal energy conversion devices. Attention is focused on traditional nanocomposites based on chalcogenide compounds Bi2Te3, PbTe, AgSbTe2, and the new structure type half-Heusler compounds and skuterudytiv. Defined strategy for further development of new nanocomposite materials with high values of thermoelectric parameters.
Keywords: Semiconductors, thermoelectricity, nanocomposites, figure of merit.
M.O. Haluschak1, V.G. Ralchenko2, A.I. Tkachuk1 ,3, D.M. Freik3
Methods of Measuring the Thermal Conductivity of Bulk Solids and Thin Films (Review)
1Ivano-Frankivsk National University of Oil and Gas, st. Carpathian, 15,
Ivano-Frankivsk, 76019, e-mail: galuschak@nung.edu.ua
2Instytut General Physics. AM Prokhorov, 119991, Moscow, ul. Vavilov, 38,
tel. +79032590675, E-mail:ralchenko@nsc.gpi.ru
3Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, E-mail:freik@pu.if.ua
Vasyl Stefanyk Prekarpathian University
Shevchenko str., 57, Ivano-Frankivsk, 76000, Ukraine, E-mail: freik@pu.if.ua
The analysis of the main methods of measuring the thermal conductivity of solids and structures are circuit installations to implement these methods have been shown. The number of theoretical and empirical formulas for calculations the thermal conductivity of materials using the described methods have been given. Reviewed accuracy for each method and analyzed the reasons why there are errors in the measurement have been measured.
Keywords: thermal conductivity, radiation techniques, solids.
T.O. Parashchuk, V.M. Chobanjuk, N.D. Freik
Thermodynamic Properties of Zinc Selenide Crystals:
Quantum-Chemical Calculation
Physical-Chemical institute, Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., 76018, Ivano-Frankivsk, Ukraine, E-mail:freik@pu.if.ua
Cluster models for zinc selenide 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 selenide, thermodynamic parameters.
I.V. Gorichok, L.D. Yurchyshyn, V.I. Makovyshyn
Thermodynamics of Point Defects in Bismuth Doped Crystals
of Germanium Telluride GeTe:Bi
Physic-Chemical 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: freik@pu.if.ua
Іnvestigated defective subsystem germanium crystals doped bismuth telluride. Established that the occurrence of impurity atoms in the crystal lattice of Bi GeTe leads to the formation of point defects substitution , which determine the dependence of the concentration of free charge carriers from impurity content and tellurium non-stoichiometric.
L.V. Turovska, V.M. Boychuk, V.V. Boryk
Point Defects and Physicochemical Properties of Crystals in Pb-Ga-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:freik@pu.if.ua
Based on the analysis of experimental results and calculations based on crystalquasichemical formulae of gallium doped lead telluride crystals type and charge state of the dominant point defects have been specified. The mechanisms of formation of PbTe-GaTe and PbTe-Ga2Te3 solid solutions have been offered. Dependences of Hall concentration of current carriers and concentration of point defects on the content of alloying compounds, the value of the initial deviation from the stoichiometric composition of lead telluride and charge state of gallium have been defined. The conditions of thermodynamic n-p-and p-n-conversions have been found.
G.Ya. Gurgula, M.P. Vadyuk, V.M. Bojchuk, T.P. Vintonjak
Crystal Chemistry of Defect Subsystem in Cobalt Doped Zinc Selenide Crystals ZnSe:Co
Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, E-mail:freik@pu.if.ua
The crystal-quasichemical formulae of doping at the Crystals n-ZnSе:Со аnd p-ZnSе:Со are suggested. The dependence on point defects concentration, on free charge carrier concentration and Hall concentration of the degree of nonstoichiometry (α, β) are calculated.
V.V. Prokopiv, B.P. Volochanska, L.Yo. Mezhylovska
Quasychemical Description of Zinc Telluride Enriched Tellurium Own Point Defects
Physical-Chemical Institute,
Precarpathion National University named after V. Stefanyk,
Shevchenko Str.,57, Ivano-Frankivsk, Ukraine
The offered model of quasychemistry reactions of own point defects formation in zinc telluride enriched tellurium crystals with simultaneous existence two-charging defects behind Schottky. On the basis of the analysis of a requirement of an electroneutrality the dependence of defects concentration both carriers of current from temperature and fractional pair pressure of a tellurium is found at embodying of two-temperature annealing. It is specify value equilibrium constants of corresponding reaction.
D.М. Freik, І.V. Gorichok, S.D. Bardashevska, G.J. Gurgula
Thermodynamics Defect Subsystem of Zinc Telluride
Vasyl Stefanyk Prekarpathian University, Shevchenko Str., 57, Ivano-Frankivsk, 76025,
Ukraine, e-mail: goritchok@rambler.ru
Using a method which based on minimizing the thermodynamic potential of the "crystal-pair" as a function of defect concentration, have been calculated equilibrium concentration of point defects and free carriers in zinc telluride crystals ZnTe depending on technological factors of two-temperature annealing (annealing temperature T and vapor pressure of zinc PZn or tellurium PTe).
D.M. Freik, L.I. Nykyruy, R.O. Dzumedzey, O.M. Voznyak, A.V. Lysak
Thermoelectric Figure of Merit Optimization of PbX (X = S, Se, Te) Crystals
Vasyl Stefanyk Prekarpathian University, Shevchenko Str., 57, Ivano-Frankivsk, 76025,
Ukraine, e-mail:freik@pu.if.ua
Calculated and analyzed values of thermoelectric parameters of lead chalcogenides crystals of n-type conductivity. We consider the efficiency of thermoelectric material - dimensionless figure of merit, the ways of its optimization. It is shown that the change of technological factors can be controlled form the dominant scattering mechanisms of the charge carriers, and hence increase the value of the resulting Q-factor of the material.
D.M. Freik1, R.O. Dzumedzey1, I.V. Goritchok1, L.I. Nukuruy1, S.I. Mudryi2
Thermoelectric Properties and Crystaloquazychemistry
of Doped Lead Telluride
1Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, E-mail:fcss@pu.if.ua
2Ivan Franko Lviv National University
8, Cyril and Methodius, Str., Lviv, 79005, Ukraine
Diffraction analysis of PbTe:Sb samples, confirming the correctness of the chosen process conditions of synthesis. The calculation of the electrical conductivity and thermoelectric coefficient doped antimony lead telluride n-PbTe:Sb. In terms crystaloquazychemistry described amphoteric properties of antimony impurities in lead telluride. Found that optimum properties are samples containing up 0.3 at.% Sb at. T ≈ 600 K.
Keywords: doping, synthesis, thermoelectric parameters, point defects.
B.M. Ruvinskii1, M.A. Ruvinskii2
The Complexes of Native Defects with Oxygen in n-PbTe Films
1Ivano-Frankivsk National Technical University of Oil and Gas, 15, Carpatska Str., Ivano-Frankivsk, 76000, Ukraine
2Vasyl Stefanyk' Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine
bruvinsky@gmail.com
On the basis of notion about formation and destruction of neutral complexes of own defects and oxygen dopant and in lead telluride films the explanation of kinetics of an electron concentration being observed at low pressures of oxygen and room temperature in n-PbTe films is proposed. The kinetic parameters of two different types of complexes had been determined from matching theoretical and experimental results.
Ya.P. Saliy I.M. Freik
Self-Organization of Periodic Nanostructures of Point Defects in the
Films IV-VI by Thermal Deposition
Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, 76000, E-mail:saliyyaroslav@gmail.com
From the analysis of the influence of parameters growing on thermoelectric properties of thin films of lead and tin chalcogenides was found that the experimental dependence of the electrical conductivity and Seebeck coefficient of PbTe films grown on polyamide film are periodic with period Δd ≈ 300 nm. Periodicity explained by assuming that host and interstitial atoms and vacancies of tellurium diffusing at high growing temperatures interact in the processes of generation and recombination. The model of exponential dependence of anionic vacancies concentration from stoichiometry deviation are considered.
Keywords: self-organization, the periodic structure, analytical dependences.
R.I. Nykyruy, V.Yu. Potyak, O.L. Sokolov
Parameters Gasdynamic Flow Vapor PbS, CdS, ZnS
Vasyl Stefanyk PreCarpathian National University
57, Shevchenko Str., Ivano-Frankivsk, e-mail:freik@pu.if.ua
Shows the expression for the thermodynamic parameters of the gas-dynamic vapor stream at a linear temperature gradient along the cylindrical channel. Dependence of Mach number, velocity ratio and the resulting condensation, vapor flux density, degree of supersaturation and critical cross section pairs cadmium sulfide, lead and zinc from the evaporation temperature of the material, the temperature gradient along the chamber walls and the dimensionless coordinates to obtain the most perfect structure.
G.E. Malashkevych1, L.Yo. Mezhylovska2, D.M. Freik2, Ya.S. Yavorskiy2
Surface Morphology and Optical Properties of Nanostructures Based on PbTe
1Molecular and Atomic Physics Institute of NASB Belarus
220072, Minsk, Independence Avenue 70, Belarus, E-mail:malash@imaph.bas-net.by
2Vasyl Stefanyk PreCarpathian University, Shevchenko Str., 57, Ivano-Frankivsk, 76025,
Ukraine E-mail:freik@pu.if.ua
The processes of growth, topology, and spectral characteristics of vapor-phase nanostructures PbTe on single crystal ((001) mica-muscovite, (111) silicon, (111) germanium) substrates and polished glass and fused quartz plates which is coated gel films have been studied. The effect of impulse and stationary heating change their structural composition and spectroscopic properties have been found. The changes slope edge of the inter band absorption of nanostructures which is based on the degree of lead telluride orientation and crystallite size as well as the temperature and duration of heat treatment have been determined.
Keywords: Lead telluride, nanostructures, topology and optical properties.
O.L. Sokolov, Ya.P. Saliy, I.S. Bylina, V.Yu. Potyak
The Processes of Formation of Vapor-Phase Condensates CdTe
Vasyl Stefanyk Precarpathian National University:
57, Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine, Е-mail: freik@pu.if.ua
Based on the analysis of AFM-studies obtained histogram distribution of nanoparticles in height, defines the maximum Dm and Dc their average lateral size and the ratio Dm/Dc and roughness Ra thin film structures CdTe, deposited on polished glass and Oxford in the method of "hot wall" at different temperatures substrates TP = (150 -250) º C evaporator TV = (400-500) ºC chamber walls TS = (TV +50) º C and deposition time t = (0,3-5) min. Within ostvald ripening growth mechanism installed vapor-phase structures.
Keywords: cadmium telluride, thin films, nanostructures, hot wall, the growth processes.
Ya.S. Yavorskyy
The Processes of Structure in Vapor-Phase Condensates PbTe:Sb at Sital
Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str.,
Ivano-Frankivsk, 76000, Ukraine, E-mail:freik@pu.if.ua
The results of AFM studies of processes of structure formation in condensates PbTe:Sb/Oxford, received open evaporation in vacuum at temperatures of deposition TP = (150-250) º C and deposition time τ = (15-240) p. It is shown that the dominant mechanism is the origin Folmer-Weber, and the process of growth nanoformations explained in approaching ostvald maturation, which is dominated by diffusion kinetic processes. In some cases formed nanostructures PbTe: Sb represent trigonal pyramids with {100} facets and the foundation (111) parallel to the substrate surface.
Keywords: nanostructures, vapor-phase methods of lead telluride, the processes of growth, maturation ostvald.
D.M. Freik1, Ya.S. Yavorskiy1, P.М. Lytvyn2, I.S. Bylina1,
І.М. Lishchynskiy1, V.B. Marusyak1
The Process of Vapor-Phase Growth of
Nanostructures PbTe: Bi at Sital
1Vasyl Stefanyk Precarpathian National University:
57, Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine, Е-mail: freik@pu.if.ua
2V. Lashkаryov Institute of Semiconductor Physics,
prospect Nauki, 41, Kyiv, 03028, Ukraine, Е-mail: plyt@isp.kiev.ua
The results of AFM-studies of processes of formation of nanostructures based on doped bismuth telluride Lead PbTe:Bi, deposited from vapor in the vacuum open to substrates with ceramics for various technological factors: temperature evaporation TV = (650-750) º C temperature substrates TP = (150 -250) º C, the deposition τ = (3-120) p. We describe the impact studied the conditions for the growth processes and structural nanoformations.
Keywords: Nanostructures, Lead Telluride, formation processes.
D.M. Freik, B.S. Dzundza, O.B. Kostyuk, G.D. Mateik
Near-Surface Layers and Thermoelectric Properties of vapor-Phase
PbTe: Bi Condensates
Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str.,
Ivano-Frankivsk, 76018, Ukraine, E-mail:fcss@pu.if.ua
Investigated thermoelectric properties of polycrystalline films of PbTe: Bi, obtained by condensation of steam in the open vacuum on ceramics substrate. Based on a two-layer model Petritz found electrical parameters subsurface layers. The results are interpreted processes of oxygen adsorption on the surface and its diffusion into the condensate. Shown that condensates thickness d <0,2 micron characterized by improved thermoelectric properties.
Keywords: thin film Lead Telluride, resistivity, mobility.
B.S. Dzundza, Ya.S. Yavorskiy, A.I. Tkachuk, Yu.V. Bandura
Influence of Interfaces on the Scattering of Charge Carriersin Doped Bismuth Telluride Films Lead
Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str.,
Ivano-Frankivsk, 76018, Ukraine, E-mail:fcss@pu.if.ua
The influence of interfaces on the scattering of charge carriers in doped bismuth telluride films of lead deposited on sital substrates on their thickness. Found that the dominant role played by scattering on the surface and within intergrain, the relative contribution is determined by the temperature of deposition.
Keywords: Lead telluride, scattering, mobility, surface.