Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices

The work is concerned with ascertainment of the regularities for thermostimulated formation of the phase composition and structure of CoSb₃-scutterudite-based films deposited by the vacuum condensation method as well as the effect of the nanoscale factor on their thermoelectric properties. Работа по...

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Published in:Успехи физики металлов
Date:2018
Main Authors: Makogon, Yu.M., Sidorenko, S.I., Shkarban, R.A.
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Language:English
Published: Інститут металофізики ім. Г.В. Курдюмова НАН України 2018
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/167901
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Cite this:Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices / Yu.M. Makogon, S.I. Sidorenko, R.A. Shkarban // Progress in Physics of Metals. — 2018. — Vol. 19, No 1. — P. 5-24. — Bibliog.: 19 titles. — eng.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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author Makogon, Yu.M.
Sidorenko, S.I.
Shkarban, R.A.
author_facet Makogon, Yu.M.
Sidorenko, S.I.
Shkarban, R.A.
citation_txt Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices / Yu.M. Makogon, S.I. Sidorenko, R.A. Shkarban // Progress in Physics of Metals. — 2018. — Vol. 19, No 1. — P. 5-24. — Bibliog.: 19 titles. — eng.
collection DSpace DC
container_title Успехи физики металлов
description The work is concerned with ascertainment of the regularities for thermostimulated formation of the phase composition and structure of CoSb₃-scutterudite-based films deposited by the vacuum condensation method as well as the effect of the nanoscale factor on their thermoelectric properties. Работа посвящена установлению закономерностей термостимулирован-ного формирования фазового состава и структуры плёнок на основе скуттерудита CoSb₃, осаждённых методом вакуумной конденсации, а также влияния фактора наноразмерности на их термоэлектрические свойства. Роботу присвячено встановленню закономірностей термостимульованого формування фазового складу та структури плівок на основі скутерудиту CoSb₃, осаджених методом вакуумної конденсації, а також впливу чинника нанорозмірности на їхні термоелектричні властивості.
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fulltext ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 5 https://doi.org/10.15407/ufm.19.01.005 PACS numbers: 68.37.Ps, 68.55.Nq, 68.60.Dv, 73.50.Lw, 82.80.Yc, 84.6Rb, 85.80.Fi Yu.M. Makogon, S.I. SIdorenko, and r.a. Shkarban National Technical University of Ukraine, ‘Igor Sikorsky Kyiv Polytechnic Institute’, 37 Peremohy Ave., UA-03056 Kyiv, Ukraine fabrication of nanosize filMs on the base of scUtterUdite cosb3 for therMoelectric devices The work is concerned with ascertainment of the regularities for thermostimulated formation of the phase composition and structure of CoSb3-scutterudite-based films deposited by the vacuum condensation method as well as the effect of the nanoscale factor on their thermoelectric properties. The influence of the substrate temperature and physical-technological parameters of heat treatment (temperature, duration, en vi ronment) on the phase composition, structure, mechanical-stress level, and thermo electric properties of the CoSbx (30 nm) (1.8 ≤ х ≤ 4.2) (65–81 at.% Sb) films is stu died. As determined, the change in the substrate temperature during the deposition of nanoscale Co–Sb films in the concentration range of 65–81 at.% Sb allows regulating the structural state. During the deposition on substrates at a room tempe rature, an X-ray amorphous state with an extended region for existence of the CoSb3-type phase at 75–80 at.% Sb after crystallization and further heating is formed. When the substrate temperature increases up to 200 °C, a crystalline state forms, and regularities of phase composition formation in Co–Sb films are charac- terized by a sequence, which is analogous to the phase equilibrium diagram for the bulk state of the Co–Sb system with the CoSb3-type phase formation at ≈75 at.% Sb. As found, films based on CoSb3 are thermally stable up to ≈300 °C. Thermal treatment of Co– Sb films with an Sb concentration of 65–81 at.%, both in vacuum and under nitrogen, at the temperatures above 300 °C, leads to the occurrence of phase trans formations and a change in the structure according to the schemes: CoSb3 + Sb → CoSb3 (at 300 °C), CoSb3 → CoSb3 + CoSb2 (at 400–500 °C), CoSb2 → → CoSb2 + CoSb (at 500–600 °C) because Sb atoms get rise in an ability to sublimate from the X-ray amorphous or crystalline states and cobalt antimonides, CoSb2 and CoSb3 , if annealing temperature increases. As determined, the presence of the nano- scale factor (i.e., the single-phase crystalline structure of CoSb3 scutterudite with an extended area of existence in the film form with increased structural imperfection due to the sublimation of antimony and reduction in the grain size) causes an increase in the thermoelectric efficiency coefficient of Co–Sb films in ≈8 times as compared to the bulk material. This has a practical importance when these materials 6 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban are used for providing the autonomous power supply for low-power electronic devices and creating film coolers in the elemental base of the nanoscale range for computer equipment and infrared sensors. Keywords: nanoscale film, heat treatment, CoSb3 scutterudite, antimonide, thermo- electric efficiency coefficient. introduction Energy saving is an important component for the economic development of countries. Most of the electric power is produced via the thermal machi- nes with a low efficiency factor (less than 40%). That is more than half of the energy dissipates as a heat for nothing. That is why the thermo- electricity based on the Seebeck (direct conversion of thermal ener gy into electrical one) and Peltier (reverse thermoelectric cooling) effects is one of the priority trends in development of science and technology. The efficiency of conversion of heat into electricity depends on the properties of a material and defined by the dimensionless value ZT— thermoelectricity efficiency coefficient proposed by A.F. Ioffe. The ZT parameter can be calculated with the formula ZT = S2Тσ/k, where S is the Seebeck coefficient, σ is an electrical conductivity, T is a temperature, k = kеl + kph is a total thermal conductivity coefficient (kеl and kph are electron and phonon components of thermal conductivity) [1, 2]. Modern traditional materials (Bi2Te3, PbTe, PbxSn1−xTe) possess a relatively low thermoelectricity efficiency coefficient ZT ≈ 0.6 [3, 4]. The problems arising in the search for new more efficient thermo- electric materials are caused by the fact that such a material must have simultaneously high electrical conductivity and low thermal conductivity. These two characteristics commonly accompany each other and their inde- pendent change remained practically unrealizable for a long time. A new trend in the search for thermoelectric materials arose in 1995, when G. Slack proposed a theory called as ‘the concept of Phonon-Glass Elec- tron-Crystals’. This is a group of special materials that can well con duct electrical energy (as a crystalline conductor) and poorly conduct thermal energy (like a glass), such as Me–Sb antimonides and Me–As arsenides, where Me is Co, Ir, Rh, Ni. Thus, a possibility to increase the energy factor S2Tσ, while decreasing the thermal conductivity k, appears [5]. Currently, the most promising material is a cobalt antimonide CoSb3 (scutterudite). In so doing, one of the ways to increase the thermoelectric efficiency coefficient of CoSb3 scutterudite is associated with application of nanoscale materials, such as nanofilms. According to theoretical calcu- lations, the conversion to nanoscale materials makes it possible to in- crease ZT up to several times due to a decrease in the thermal conductivity as a result of an increase in phonon scattering by the structural defects— grain and layer boundaries that can be of nanoscale size [6–8]. ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 7 Fabrication of Nanosize Films for Thermoelectric Devices Nowadays, the topical material science problems in the field of thermoelectricity are as follows. First, it is the creation of new materials, including nanomaterials with ZT > 1 at high operating temperatures. Second, it is the establishment of a connection between the phase composition, structure, properties, functional stability and operational reliability during the conversion to nanoscale materials to enhance competitiveness with other methods of generating electricity. In this case, heat treatment is a key technological operation in the creation of a new functional material with high thermoelectric properties and performance characteristics. In addition, there are practically no studies on the formation of CoSb3 scutterudite-based films by the physical deposition methods. The goal of the paper is to ascertain the behaviour characteristics for the processes of thermally stimulated formation of the phase composition and structure in the 30 nm CoSbx films (1.8 ≤ x ≤ 4.2; Sb concentration belongs to the range of 65–81 at.%) obtained by molecular beam deposition on a SiO2 substrate (100 nm)/Si(001). Еxperimental Part The samples for the study were obtained at the Department of Surface Physics and Interfaces on the MBSI equipment of SGC600 series due to the cooperation within the framework of international DAAD projects according to L. Euler programs (ID No. 08/01145 in 2008–2009 and No. 50744282 in 2010–2011). Measurements of thermoelectric parame- ters were carried out by our German partner side [9, 10]. The CoSbx (1.8 ≤ x ≤ 4.2) (65–81 at.% Sb) films with thickness of 30 nm were obtained by molecular beam deposition under ultrahigh vacuum (≈7 ⋅ 10−9 Pa) on the substrates of single-crystal Si (001) with a 100 nm thick layer of SiO2 dioxide. An ultrahigh vacuum allowed elimi- nation of the influence of the polluting atoms of the residual atmosphere (N2, O2, Ar, etc.) on the phase composition and structure during deposition and heat treatment of nanoscale films. The presence of SiO2 oxide layer served as a barrier preventing the interdiffusion of the CoSb film with substrate silicon and silicide formations. The substrate was rotated in order to reach the uniform deposition. The main physical and technological parameters, the change of which allows to obtain films with different phase composition and structure (crystalline and X-ray amorphous), were as follows: the deposition rate of elements, the substrate temperature, the medium, the temperature and the duration of their subsequent annealing. The substrate temperature (Ts) was either room temperature or 200 °C. Antimony (Sb) was precipi- tated with an effusion (using a Knudsen cell) heated to the temperature of 470 °C at a constant rate of 0.3 Å/s. Cobalt (Co) was vaporized by the 8 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban electron beam method. The change in the chemical composition was achieved by varying the deposition rate Co in the range of 0.027– 0.049 Å/s at a constant deposition rate of Sb. The deposition rate Co was measured with a vapour flow density sensor. To calibrate the Sb deposition rate at different temperatures of substrate and obtain required thickness, the Rutherford backscattering (RBS) data were used. The film thickness was additionally controlled by X-ray reflectometry along with quartz resonator. The statistical error value during measuring the film thickness was ±1 nm. After the preci- pi tation, the samples were annealed in a vacuum or in a nitrogen at- mosphere. Annealing of the samples was carried out on a VUP-5 equip- ment in a vacuum (≈10−3 Pa) in the temperature range 100–700 °C with a holding time of 30 s, 0.5 hour and 1 hour. Annealing in a nitrogen atmosphere was performed on a high-speed heat treatment unit AST SHS 10 within the temperature range 300–700 °C during 30 seconds. To determine the thermal stability of Co–Sb films, the long-time annealing in a vacuum during 2–5 hours was carried out. To study the phase composition and structure of the films, we appli- ed a set of methods of the physical materials science. They are X-ray diffraction phase analysis, the Debye–Scherrer method with photo- graphic X-ray registration on the URS-55 equipment (λKα-Co radiation, exposure time up to 30 hours), survey on the DRON UM-1 diffractometer (λKα-Fe radiation), and Rigaku Ultima IV (λKα-Cu radiation). The survey was performed for an angle range 2θ ∈ [10–80°] with a step of 0.02° and a waiting time of 2 s at one point. Measurements of the mechanical residual stresses in the samples were carried out using X-ray tensometry— the sin2ψ method by the diffraction reflex (310) of the CoSb3 phase. The average size of the coherent scattering regions (CSR) was calculated via the Debye–Scherrer formula. The chemical composition was determined by the Rutherford backscattering methods with an accuracy of ±1 at.%, using He+ ions accelerated by an energy of 1.7 MeV. The layer-by-layer chemical analysis was performed by the method of mass spectrometry of secondary neutrals (MSSN) on the Specs INA-X device. Electroconducti- vity properties were measured by a four-probe method. To study the morphology of the surface of nanosized films, we used both scanning electron microscopy (SEM, REMMA-106I) and atomic force microscopy (AFM, Dimension 3000). Two methods for determining the quantitative phase composition were used. The first one is the metallographic method of ‘secants’ using the Image-Pro Plus v.7.0 software based on the results of analysis of images obtained by the scanning electron microscopy. The second method is based on A.A. Ru sakov’s technique using the ratio of the intensities of the diffraction maxima on diffractograms for the films with a two-phase composition. ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 9 Fabrication of Nanosize Films for Thermoelectric Devices results and discussions The CoSbx films (30 nm; 1.8 ≤ x ≤ 4.2; 65–81 at.% of Sb) deposited on the substrate at room temperature are in the X-ray amorphous state since it is confirmed by X-ray diffraction analysis data, namely, there no diffraction maxima on the diffractograms (Fig. 1). The heating of X-ray amorphous films in the temperature range of ≈140–200 °C results to their crystallization (Fig. 2). The process of transformation into a crystal state in the CoSbх (2.6 ≤ х ≤ 4.1) 30 nm films is accompanied with an abrupt (jump) in- crease in electrical conductivity (Fig. 3, а, b). As established using the Fig. 1. X-ray patterns of as-deposited CoSb3.5 film on substrate at a room tempera- ture and after heating (λKαβ-Fe) Fig. 2. Changing of a lattice parameter а for CoSb3 phase after heating of Co–Sb films up to 200 °C Fig. 3. Dependence of electrical resistance of CoSb3.0 (a) and CoSb4.1 (b) films on heat- ing temperature (substrate temperature Ts = 20 °C) 10 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban X-ray struc tural phase analysis and resistometry, if the Sb con- centra tion increases, the tempe- rature range of crystallization of the investiga ted films shifts toward higher temperatures and amounts 140–200 °C (Fig. 4). Electrophysical properties of the films depend on their che- mical and phase compositions. Phase composition affects a tem- perature dependence of the re- sis tivity R = f (Т). After crys tal- lization from X-ray amor phous state in CoSb3.0 film, the dependence R = f (Т) has a semiconductor character with ionic conductivity type (Fig. 3, а). In CoSb3.5 film with an abundant Sb concentration (more than 75 at.%), the temperature dependence of conductivity has a metallic behaviour (Fig. 3, b). X-ray structural phase analysis showed that after crystallization of X-ray amorphous films, a single-phase composition corresponding to Table 2. Phase composition of the as-deposited CoSbx 30 nm thick films, where 1.8 ≤ x ≤ 4.2 (65–81 at.% Sb) Тs , °С Concentration of Sb (cSb) in the film, at.% 65 71 72 75 76 78 81 Phase state after as-deposition 20 X-ray amorphous state 200 CoSb2 CoSb3 + + CoSb2 CoSb3 + + CoSb2 CoSb3 CoSb3 + Sb CoSb3 + Sb CoSb3 + Sb Fig. 4. Influence of Sb content on a crystal- lization range for Co–Sb films Table 1. Phase composition after heating of X-ray amorphous 30 nm thick CoSbх (2.4 ≤ х ≤ 4.1; 72–80 at.% Sb) films Т, °С Concentration of Sb (cSb) in the film, at.% 72 75 78 80 Phase composition of nanosize Co–Sb films after heating 100 X-ray amorphous state 200 CoSb3 + CoSb2 CoSb3 CoSb3 CoSb3 Phase composition of Co–Sb in a bulky state after heating 200 CoSb3 + CoSb2 CoSb3 CoSb3 + Sb CoSb3 + Sb ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 11 Fabrication of Nanosize Films for Thermoelectric Devices Fig. 5. X-ray diffraction (a) and Debye powder (b) patterns for Co–Sb films after deposition on SiO2 (100 nm)/Si(001) substrates at Ts = 200 °C (radiation: λKα-Cu (a), λKαβ-Cо (b)) CoSb3 scutterudite was observed in a wide concentration range of 75– 80 at.% Sb. The large values of the lattice parameter a for the CoSb3 phase as compared to those for a bulk state of the material indicate that atoms of abundant antimony occupy voids in the unite crystal cell (Fig. 2). These results indicate that region of existence of scutterudite CoSb3 (75–80 at.% Sb) broadens by 5% (Table 1). Fig. 6. A change in a ratio of diffraction reflection intensities as a function of Sb content: (a) I (210)CoSb/I (310) CoSb3 and I(310) CoSb3/I(210) CoSb2 in the films with cSb ≤ 75 at.%, (b) I (012) Sb/I(310) CoSb3 and I(310) CoSb3/I(012) Sb in the films with cSb > 75 at.% 12 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban After deposition on a sub- strate at a temperature of 200 °С, the CoSbх (1.8 ≤ х ≤ 4.2) films had a crystal structure (Fig. 5). The diffraction maxi- mum intensities for the films coincide with those values for the bulky material; this fact indicates that films are in a non-textured poly crystalline state. In the film containing 75 at.% Sb, the scutterudite CoSb3 crys- tallizes during the deposition. In the films with Sb con cen tra- tion less than 75 at.%, the CoSb2 antimonide is formed additio- nally to the CoSb3 . In the samples with abundant Sb con- centration (more than 75 at.%), two phases appear: CoSb3 and Sb (Fig. 5). The decrease in the ratio of the diffraction maximum inten- sities I(210) CoSb2 /I(310) CoSb3 in the films for a concentration range cSb ∈ [65 at.%, 75 at.%] indicates that CoSb3 phase in- crease (Fig. 6, а). While the chan ge in the ration of the dif fraction reflections I(012) Sb/I(310) CoSb3 in the range 75 at.% < cSb ≤ 81 at.% indicates that phase CoSb3 decreases as the Sb concentration increases (Fig. 6, b). This is also in agre ement with results of quantity metallographic analysis of the pat terns obtained via the SEM. Thus, using the molecular-beam deposition method to vary the tem- pe rature, we can obtain X-ray amorphous (at 20 °C) and crystalline (at 200 °C) states. The phase composition formation in the nanosized films deposited at 200 °C de pends on the Sb content and occurs accor dingly to the predictions in the equilibrium phase diagram for the bulky state of the Co–Sb system (Table 2). The change in the phase composition of the films results to the chan ge in the resistivity. The Sb-concentration-dependence of resistivity has a parabolic behaviour for the films with a maximum at 75 at.% of Sb. The CoSb3 scutterudite is a more high-resistant phase as com pared with both CoSb2 and Sb (Fig. 7). Fig. 8. Dependence of the roughness for Co–Sb films on the Sb concentration Fig. 7. Effect of antimony content on elec- trical resistance of Co–Sb films ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 13 Fabrication of Nanosize Films for Thermoelectric Devices Atomic force microscopy data demonstrate that a surface roug h ness of the films has a minimal value of 3–5 nm in the single-phase structures (Fig. 8). It contributes to the minimization of the resistivity and hence enhances a thermoelectric efficiency coefficient ZT. Figure 9 exhibits the surface morphology for 30 nm thick films CoSbx (1.8 ≤ х ≤ 4.2; 65–81 at.% Sb) and shows qualitative model of the phase state formation in the nanosized films deposited on a substrate at 200 °C. One can easy see that in process of deposition, a scutterudite forms for Fig. 10. Change of RBS spectra of CoSb3.6 film (78 at.% Sb) after deposition at Ts = 20 °C and annealing in vacuum (a). Concentration of antimony as a function of annealing temperature (b) Fig. 9. The morphology of the surface of 30 nm thick CoSbx (1.8 ≤ x ≤ 4.2; 65– 81 at.% Sb) films after deposition at Ts = 200 °C: (above) surface images obtained by SEM; (in the middle) qualitative model concepts on the phase composition forma- tion; (below) surface images obtained by AFM 14 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban ≈75 at.% Sb (homo ge neous system), while decrease or increase of antimony content leads to the formation of additional pha ses (hete rogeneous system). When the Sb-rich films CoSb3.6 and CoSb4.2 with a two-phase com- position (scutterudite CoSb3 and crystalline antimony Sb) are subjected to annealing in a vacuum above 500 °C, the ratio of the intensities of the diffraction reflections I (210) Sb/I (310) CoSb3 decreases. The results of Rutherford backscattering show that content of antimony in the films decreases after annealing (Fig. 10). For instance, one can see on the RBS spectra in Fig. 10, a that the intensity of the energy level for antimony decreases after annealing of the CoSb3.5 film in vacuum at 610 °C during 30 s, and antimony concentration decreases by ≈10 at.% (Fig. 10, b). This is due to the sublimation of antimony during annealing. We used a method of mass spectrometry of secondary neutrals for per- forming a layer-by-layer chemical analysis of atomic distribution over the thickness of CoSb4.1 (30 nm)/SiO2 (100 nm)/Si (001) sample. The obtained results showed that there is no the interdiffusion of the film and substrate atoms (Fig. 11, a). There is no also a formation of silicides. As the annealing temperature rises up to 610 °C, the curves describing concentration dis- tribution of elements show a reduction in the intensity attributed to an- timony due to decrease of its concentration in the film (Fig. 11, c). Fig. 11. The layer-by-layer distri bu- tions of elements in CoSb4.1 (30 nm)/ SiO2 (100 nm)/Si (001) after deposi- tion and annealing in vacuum at 350 °C and 610 °C ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 15 Fabrication of Nanosize Films for Thermoelectric Devices The emergence of a signal due to silicon is explained by the presence of voids with a depth reaching the substrate, i.e. voids occupy all thick- ness of the film [12]. A gradual atomization of material is a feature of the MSSN technique, therefore elements of the film surface and silicon substrate begin to produce a signal simultaneously during the chemical analysis (Fig. 11, c). The annealing of films, where the concentration of Sb is close to its content in a scutterudite in vacuum above 300 °C, results in the change of the phase composition. One can see the appearance of the CoSb2 reflexes in the diffraction pattern and growth of the intensity ratio I (210) CoSb2 /I (310) CoSb3 in the absence of texture (Fig. 12, a). This indicates that CoSb2 phase grows, while CoSb3 one reduces. Therewith, the parameter a of the cubic crystal lattice of scutterudite decreases (Fig. 12, b), and for the most part a decreases in the films after crys- tallization from the X-ray-amorphous state. Such a change in the phase composition is attributed to the partial sublimation of Sb atoms out of CoSb2 and CoSb3 crystal lattices during annealing in the nitrogen atmosphere as well as vacuum due to the phase transformations according to the schemes: 300 C (Sb ) 400 500 C (Sb ) 3 3 3 2CoSb Sb CoSb CoSb CoSb ,> ° ↑ > − ° ↑+ → → + 500 600 C (Sb ) 2 2CoSb CoSb CoSb.> − ° ↑→ + Detailed data about an effect of annealing conditions on the formation of phase composition and structure of nanosize Со–Sb films are reported in our previous paper [11]. Fig. 12. Influence of annealing temperature for CoSb3.6 and CoSb4.2 films (in vacuum) on the change of (a) ratio of intensities I (012) Sb/I (310) CoSb3 of diffraction reflec- tions and (b) the lattice parameter a for CoSb3 phase 16 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban The annealing of CoSbx crystal films (30 nm; 3.2 < x < 4.2) initially results to sublimation of excess Sb, then chemical bonds in CoSb3 and CoSb2 antimonides are broken. One part of the released antimony atoms Table 3. Phase composition of thick CoSbx films of 30 nm (1.8 ≤ x ≤ 4.2; 65–81 at.% Sb) after annealing in the vacuum Т, °С Concentration of antimony in the film (cSb), at.% 65 71 72 75 76 78 81 Phase composition after annealing 300 CoSb3 + + Sb CoSb3 + + Sb CoSb3 + + Sb 400 CoSb3 + + CoSb2 CoSb3 + + CoSb2 CoSb3 + + CoSb2 CoSb3 CoSb3 + + Sb CoSb3 + + Sb 450 CoSb3 + + CoSb2 CoSb3 + + CoSb2 CoSb3 CoSb3 + + Sb CoSb3 + + Sb 600 CoSb2 + + CoSb CoSb3 + + CoSb2 CoSb3 + + CoSb2 CoSb3 + + CoSb2 CoSb3 CoSb3 + + Sb 650 CoSb3 + + CoSb2 CoSb3 + + CoSb2 Fig. 13. X-ray diffraction patterns for CoSb3.3 (a) and Debye powder patterns for CoSb2.9 (b) 30 nm thick films after deposition on a substrate at 200 °C and annealing in vacuum within the temperature range of 260–610 °C (λKαβ-Fe (а), λKαβ-Cо (b)) ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 17 Fabrication of Nanosize Films for Thermoelectric Devices forms CoSb2 or CoSb with a lower content of Sb, while another part of diffusion-stimulated antimony accumulates atoms at the grain boundar- ies where then sublimes (Fig. 13). In the crystalline films obtained from the X-ray amorphous state, the excess antimony initially goes out from the voids of the crystal lat- tice, and then sublimes. The generalized experimental data on the deter- mination of the phase composition after annealing in vacuum are pre- sented in Table 3. An influence of phase transformations on the structure of films ref- lects in contraction of the sizes of grains and regions of coherent scat- tering with an increase of annealing temperature due to the sublimation of Sb (Fig. 14, а). Furthermore, the structure imperfection rises: the extension of grain boundaries increases, nanosize voids appear. The grain size in the CoSb3 film is lower in comparison to the films with a two-phase composition (Fig. 14, b). This tendency continues even after annealing. These values are three times lower as compared with a ma terial in the bulky condition [12]. Combination of such factors contri butes to increase in a ther- moelectric efficiency coefficient (ZT) due to decrease in a thermal conductivity coefficient. We revealed that a thermal stability of the CoSb3-based nanosize films is conserved up to ≈300 °C, which is evidenced by the fact that the ratio of the most intense diffraction maxima for the CoSb3 and Sb phases remains unchanged during the long-time annealing (Fig. 15) [13, 14]. The rate of sublimation of antimony at different annealing tempe- ratures above the 300 °C was used to estimate the activation energy (Ea) of this process according to the Arrhenius equation. Fig. 14. The size dependences of CoSb3 CSR phase on the annealing temperature in vacuum (a) and Sb-concentration of grain after deposition at Ts = 200 °C (b) in the Co–Sb films 18 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban Annealing of X-ray amor pho us films leads to a more in tense sub- limation process than in case of crystalline films. This is reflected in the fact that the value of Ea is 2–3 times smaller as compared to the films with a crystalline structure, where lar ger values of the energy are nee- ded to break existing chemi cal bonds that have not yet for med insuf fi- ciently in the X-ray amorphous films (Fig. 16). Thus, sublimation mecha nisms depend on the structural state of the films. When the X-ray amorphous films undergo the an nealing, anti mony partially sublimes during the formation of the crystal lattice. When the crystalline films are annealed after breaking of chemical bonds, Sb initially diffuses to the grain boundaries, and then sublimates therefrom (Fig. 17, c). The change in the phase composition of the films affects level of the stressed state. Calculated mechanical stresses in the films after their depo sition and thermal annea ling have different character and mecha- nism. They emerge due to, firstly, mismatch of the tem pe- rature coeffi cient of linear ex- pan sion of CoSb3-based film (α = = 8.8 · 10−6 K−1) and SiO2(100 nm)/ Si (001) substrate (α = 2.6 · 10−6 K−1), and secondly, due to the phase transformations when Sb subli- mates during thermal an ne a ling. This leads to a decrease in the volume of the film during the sublimation of antimony and the formation of irreversible ten si- le stresses. Fig. 16. Dependence of activation ener gy for Sb sublimation in Co–Sb films Fig. 15. Dependence of the intensity ratio of the I (012) Sb/I (310) CoSb3 diffraction peaks for CoSb3.6 (a) and CoSb4.2 (b) films on the annealing time in vacuum within the temperature range of 300–500 °C ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 19 Fabrication of Nanosize Films for Thermoelectric Devices The change in residual stres ses after deposition and after anneal- ing, as the resultant two mechanisms of their formation, showed that the level of tensile mechanical stresses after annea ling at a temperature of 500 °C increases by a factor of ≈5 (Fig. 18). This is accompanied by a decrease in the size of the co- herent scattering regions upon sublimation of Sb (Fig. 14, a) and leads to the appearance of cracks in the film and its fur- ther de gradation (Fig. 17, b and c) [16]. The thermoelectrical effici- en cy coefficient ZT for CoSb3.0 film is ≈1 at 500 °С [9, 10], this is ≈8 times higher as compared with the material in a bulky sta te when ZT ≈ 0.12 [12] (Fig. 19). CoSb4.1 film with excess of Sb has lower values of ZT ≈ 0.2. The effect of increasing of ther- mo electric efficiency coefficient is caused by the nanosize factor: the pre sen ce of single-phase crys- tal struc ture of CoSb3 scut te ru- dite with an exten ded exis tence region (75–80 at.% Sb) in the film, and enhanced structural imper fection due to antimony subli ma tion—decrease in grain sizes and increase in extent of grain boun daries. In further studies, to in crea- se the ZT, we plan to dope of nanosize Co–Sb films with dif- Fig. 19. Temperature-dependent thermoelect- ric efficiency coefficient in the Co–Sb films Fig. 18. Mechanical stresses vs. annealing temperature in CoSb3.6 film Fig. 17. Morphology of CoSb3.1 film after annealing in a nitrogen atmosphere during 30 s at 300 °C (a), 500 °C (b), and 700 °C (c) 20 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban ferent chemical elements Fe, Yb, Li, Eu, La, Се, Ba to form a structure that can better conduct electric current (as a crys talline conductor) and poorly conduct a heat (like a glass). This will make possible to reduce a phonon component of the heat conductivity and much more increase thermoelectric efficiency coefficient ZT. Doping elements occupy voids in the crystal lattice—atomic polyhedrons of large sizes. This provides an effective phonon scattering, which in turn results to decreasing of the heat conductivity without a substantial im pact on electrical conductivity due to mainly ionic character of interaction between phonons and atoms of scutterudite carcass and covalently bon- ded carcass with a small probability of chemical bonds [16–19]. Сonclusions We used a complex of different methods of investigation in order to reveal the main laws of formation of phase composition and structure, to determine electrophysical properties of Co–Sb nanosize films after deposition and annealing in vacuum and nitrogen atmosphere. It is shown that deposition of Co–Sb films (with 65–81% of Sb) on the substrates at a room temperature results to the formation of X-ray amorphous state of condensed material with an extended region for existence of the CoSb3 (75–80 at.% Sb) phase at a further heating after crystallization. In case of a deposition of Co–Sb films (65–81 at.% Sb) on the substrates at 200 °C, the crystal state of condensed material forms in accordance with the phase equilibrium diagram for a bulky state of the Co–Sb system. The nanosize CoSb3 films are stable up to ≈300 °С. Increase of the temperature of annealing in both vacuum and nitrogen atmosphere results to the sublimation of abundant antimony in the crystal or X-ray amorphous state and from CoSb2 and CoSb3 phases, which is reflected in the changing of phase composition and structure accordingly to the schemes as follows: 300 C (Sb ) 400 500 C (Sb ) 3 3 3 2CoSb Sb CoSb CoSb CoSb ,> ° ↑ > − ° ↑+ → → + 500 600 C (Sb ) 2 2CoSb CoSb CoSb.> − ° ↑→ + We revealed that the process of Sb sublimation is much more inten- sive for annealing of Co–Sb X-ray amorphous films. Activation energy for X-ray amorphous films being annealed in vacuum is ≈65 kJ/mole, which is ≈2–3 times lower in comparison to the films with crystal com- position. As shown, after deposition of nanosize Co–Sb film (with abundant concentration of antimony), there are slight mechanical stresses ≈1 GPa. ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 21 Fabrication of Nanosize Films for Thermoelectric Devices After the thermal annealing, these stresses increase up to ≈1 GPa, grain sizes decrease, cracks appear, and film material degrades. There is a nanosize factor—a single-phase crystal structure of CoSb3 scutterudite with extended existence region (75–80 at.% Sb) in the film with high structural defectiveness due to nanosize grains that decrease as annealing temperature increases during antimony sublimation. This nanosize effect causes increase in thermoelectric efficiency coefficient at 500 °C (ZT ≈ 1) as compared with that for material in a bulky state (ZT ≈ 0.12). Аcknowledgements. The authors are grateful to colleagues from Depar tment of Surface and Interface Physics at Institute of Physics of Technische Universität Chemnitz (Germany), particularly head of the department Prof. M. Al brecht, Drs. M. Daniel and G. Beddies for the fab rication of samples, help during the investigations, and discussing the results. This work was financially supported by the German scientific exchange organization (DAAD) within the framework of the Euler prog- ram (grants No. 08/ 01145 and No. 50744282). REFERENCES А.F. Ioffе, 1. Ehnergeticheskie Osnovy Termoelektricheskikh Batarey iz Polupro- vodnikov [Energy Basis of Thermoelectric Semiconductor Batteries] (Мoscow- Leningrad: AN SSSR.: 1950) (in Russian). А.О. Epreman, V.М. Аrutyunyan, and А.I. Vаganyan, 2. Alternative Energy and Ecology (ISJAEE), 25, No. 5: 7 (2005) (in Russian). А.V. Shevelkov,3. Russ. Chem. Rev., 77, No. 1: 1 (2008). M. Carle, P. Pierrat, C. Lahalle-Gravier, S. Scherrer, and H. Scherrer, 4. J. Phys. Chem. Solids, 56: 201 (1995). G.A. Slack, New Materials and Performance Limits for Thermo electric Cooling, 5. CRC Handbook of Thermoelectrics (Ed. D.M. Rowe) (Boca Raton: CRC Press: 1995), p. 407. D.М. Freik, М.О. Galuschak, О.S. Krunutcky, and О.М. Matkivskiy, 6. Physics and Chemistry of Solid State, 14, No. 2: 300 (2013) (in Ukrainian). X.J. Zheng, L. Zhu, and Y.-H. Zhou, 7. Applied Phys. Lett., 87: 242101 (2005). J. Sommerlatte, K. Nielsch, and H. Bottner, 8. Physik Journal, 6, Nr. 5: 35 (2007) (in German). D. Zhao, Ch. Tian, Y. Liu, Ch. Zhan, and L. Chen, 9. J. Alloys and Compounds, 509: 3166 (2011). Yu.N. Makogon, E. P. Pavlova, S.I. Sidorenko, D. Bеkе, А. Csik, and R.А.10. Shkar- ban, Metallofiz. Noveishie Tekhnol., 36, No. 12: 1621 (2014) (in Russian). Yu. M. Makogon, S. I. Sidorenko, and R. А. Shkarban, 11. Metallofiz. Noveishie Tekhnol., 39, No. 5: 677 (2017) (in Russian). Yu.N. Makogon, S.I. Sidorenko, and R.А. Shkarban, 12. Metaloznavstvo ta Obrobka Metaliv, No. 1 (77): 39 (2016) (in Ukrainian). 22 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban M.V. Daniel, C. Brombacher, G. Beddies, N. J13. öhrmann, M. Hietschold, D.C. John- son, Z. Aabdin, N. Peranio, O. Eibl, and M. Albrecht, J. Alloys and Compounds, 624: 216 (2015). M.V. Daniel, L. Hammerschmidt, C. Schmidt, F. Timmermann, J. Franke, N. J14. öhr- mann, M. Hietschold, D.C. Johnson, B. Paulus, and M. Albrecht, Phys. Rev. B, 91: 085410 (2015). C. Caylor, A.M. Stacy, B. Bloom, R. Gronsky, T. Sands, W.W. Fuller-Mora, 15. A. Ehr lich, D. Song, and G. Chen, IEEE 18th International Conference on Thermoelectrics (August 29–September 2, 1999), p. 657. N.R. Dilley, E.D. Bauer, M.B. Maple, S. Dordevic, D.N. Basov, F. Freibert, 16. T.W. Darling, A. Migliori, B.C. Chakoumakos, and B.C. Sales, Phys. Rev. B, 61, No. 7: 4608 (2000). G.A. Lamberton Jr., S. Bhattacharya, R.T. Littleton IV, M.A. Kaeser, 17. R.H. Tedstrom, and T.M. Tritt, Appl. Phys. Lett., 80, No. 4: 598 (2002). J.Y. Peng, P.N. Alboni, J. He, B. Zhang, Z. Su, T. Holgate, N. Gothard, and 18. T.M. Tritt, J. Appl. Phys., 104: 053710 (2008). A. Harnwunggmounga, K. Kurosakia, Y. Ohishia, H. Muta, and Sh. Yamanaka, 19. J. Alloys and Compounds, 509: 1084 (2011). Received November 7, 2017; in final version, March 12, 2018 Ю.М. Макогон, С.І. Сидоренко, Р.А. Шкарбань Національний технічний університет України «Київський політехнічний інститут імені Ігоря Сікорського», просп. Перемоги, 37, 03056 Київ, Україна ВИГОТОВЛЕННЯ НАНОРОЗМІРНИХ ПЛІВОК НА ОСНОВІ СКУТЕРУДИТУ CoSb3 ДЛЯ ТЕРМОЕЛЕКТРИЧНИХ ПРИЛАДІВ Роботу присвячено встановленню закономірностей термостимульованого форму- вання фазового складу та структури плівок на основі скутерудиту CoSb3, осадже- них методом вакуумної конденсації, а також впливу чин ни ка нанорозмірности на їхні термоелектричні властивості. Вивчено вплив температури підкладинки та фізико-технологічних параметрів (температура, тривалість, середовище) тер- мічного оброблення на фазовий склад, структуру, рівень механічних напружень і термоелектричні влас тивості плівок CoSbх товщиною у 30 нм (1,8 ≤ х ≤ 4,2; 65–81 ат.% Sb). Визначено, що зміна температури підкладинки при осадженні нано роз мірних плівок Co–Sb у концентраційному інтервалі 65–81 ат.% Sb умож- ливлює реґулювати структурний стан. При осадженні на підкладинки за кімнат- ної температури формується рентґеноаморфний стан з розширеною областю іс- нування фази CoSb3 75–80 ат.% Sb після кристалізації при подальшому нагрі- ванні. При збільшенні температури підкладинки до 200 °C утворюється криста- лічний стан, і закономірності формування фазового складу в плівках Co–Sb ха- рактеризуються послідовністю, яка аналогічна діяграмі фазової рівноваги станів для масивної системи Co–Sb з утворенням фази CoSb3 при ≈75 ат.% Sb. Вста- новлено, що плівки на основі CoSb3 термічно стабільні до ≈300 °С. Термічне об- роблення плівок Co–Sb з концентрацією Sb 65–81 ат.% як у вакуумі, так і в атмосфері азоту при температурах вище 300°С приводить до перебігу фазових ISSN 1608-1021. Usp. Fiz. Met., 2018, Vol. 19, No. 1 23 Fabrication of Nanosize Films for Thermoelectric Devices перетворень і зміни структури за схемами: CoSb3 + Sb → CoSb3 (при 300 °C), CoSb3 → CoSb3 + CoSb2 (при 400–500 °C), CoSb2 → CoSb2 + CoSb (при 500–600 °C) внаслідок зростаючої зі збільшенням температури відпалювання здатности ато- мів Sb до сублімації як з рентґено аморфного або кристалічного станів, так і з антимонідів кобальту CoSb2 і CoSb3. Визначено, що наявність чинника нанороз- мірности (однофазної кристалічної структури скутерудиту CoSb3 з розширеною областю існування в плівці з підвищеною структурною дефектністю за рахунок сублімації сурми і зменшення розміру зерен) зумовлює підвищення коефіцієнта термоелектричної ефективности плівок Co–Sb у ≈8 разів у порівнянні з масив- ним матеріялом. Це має практичну значимість при використанні цих матеріялів для забезпечення автономним живленням малопотужних електронних пристроїв і при створенні плівкових холодильників в елементній базі нанорозмірного дія- пазону для комп’ютерної техніки та інфрачервоних давачів. Ключові слова: нанорозмірна плівка, термічне оброблення, скутерудит CoSb3, антимонід, коефіцієнт термоелектричної ефективности. Ю.М. Макогон, С.И. Сидоренко, Р.А. Шкарбань Национальный технический университет Украины «Киевский политехнический институт имени Игоря Сикорского», просп. Победы, 37, 03056 Киев, Украина ИЗГОТОВЛЕНИЕ НАНОРАЗМЕРНыХ ПЛЕНОК НА ОСНОВЕ СКУТТЕРУДИТА CoSb3 ДЛЯ ТЕРМОэЛЕКТРИЧЕСКИХ ПРИБОРОВ Работа посвящена установлению закономерностей термостимулированного фор- мирования фазового состава и структуры пленок на основе скуттерудита CoSb3, осаждённых методом вакуумной конденсации, а также влияния фактора нано- размерности на их термоэлектрические свойства. Изучено влияние температуры подложки и физико-технологических параметров (температура, продолжитель- ность, среда) термической обработки на фазовый состав, структуру, уровень ме- ханических напряжений и термоэлектрические свойства пленок CoSbx толщиной 30 нм (1,8 ≤ х ≤ 4,2; 65–81 ат.% Sb). Определено, что изменение температуры подложки при осаждении наноразмерных плёнок Co–Sb в концентрационном интервале 65–81 ат.% Sb позволяет регулировать структурное состояние. При осаждении на подложки при комнатной температуре формируется рентгеноамор- фное состояние с расширенной областью существования фазы CoSb3 75–80 ат.% Sb после кристаллизации при дальнейшем нагреве. При увеличении температу- ры подложки до 200 °C образуется кристаллическое состояние, и закономерно- сти формирования фазового состава в пленках Co–Sb характеризуются последо- вательностью, которая аналогична диаграмме фазового равновесия состояний для массивной системы Co–Sb с образованием фазы CoSb3 при ≈75 ат.% Sb. Установлено, что пленки на основе CoSb3 термически стабильны до ≈300 °С. Тер- мическая обработка пленок Co–Sb с концентрацией Sb 65–81 ат.% как в вакуу- ме, так и в атмосфере азота при температурах выше 300°С приводит к протека- нию фазовых превращений и изменению структуры по схемам: CoSb3 + Sb → → CoSb3 (при 300 °C), CoSb3 → CoSb3 + CoSb2 (при 400–500 °C), CoSb2 → CoSb2 + + CoSb (при 500–600 °C) вследствие растущей с увеличением температуры от- жига способности атомов Sb к сублимации как с рентгеноаморфного или крис- 24 ISSN 1608-1021. Prog. Phys. Met., 2018, Vol. 19, No. 1 Yu.M. Makogon, S.I. Sidorenko, аnd R.A. Shkarban таллического состояний, так и из антимонидов кобальта CoSb2 и CoSb3. Опре- делено, что наличие фактора наноразмерности (однофазной кристаллической структуры скуттерудита CoSb3 с расширенной областью существования в плёнке с повышенной структурной дефектностью за счёт сублимации сурьмы и умень- шения размера зёрен) обуславливает повышение коэффициента термоэлектриче- ской эффективности плёнок Co–Sb в ≈8 раз по сравнению с материалом в массив- ном состоянии. это имеет практическую значимость при использовании этих материалов для обеспечения автономным питанием маломощных электронных уст ройств и при создании плёночных холодильников в элементной базе нанораз- мерного диапазона для компьютерной техники и инфракрасных датчиков. Keywords: nanoscale film, heat treatment, CoSb3 scutterudite, antimonide, thermo- electric efficiency coefficient.
id nasplib_isofts_kiev_ua-123456789-167901
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
issn 1608-1021
language English
last_indexed 2025-11-29T09:42:32Z
publishDate 2018
publisher Інститут металофізики ім. Г.В. Курдюмова НАН України
record_format dspace
spelling Makogon, Yu.M.
Sidorenko, S.I.
Shkarban, R.A.
2020-04-14T19:39:22Z
2020-04-14T19:39:22Z
2018
Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices / Yu.M. Makogon, S.I. Sidorenko, R.A. Shkarban // Progress in Physics of Metals. — 2018. — Vol. 19, No 1. — P. 5-24. — Bibliog.: 19 titles. — eng.
1608-1021
PACS: 68.37.Ps, 68.55.Nq, 68.60.Dv, 73.50.Lw, 82.80.Yc, 84.60.Rb, 85.80.Fi
DOI: https://doi.org/10.15407/ufm.19.01.005
https://nasplib.isofts.kiev.ua/handle/123456789/167901
The work is concerned with ascertainment of the regularities for thermostimulated formation of the phase composition and structure of CoSb₃-scutterudite-based films deposited by the vacuum condensation method as well as the effect of the nanoscale factor on their thermoelectric properties.
Работа посвящена установлению закономерностей термостимулирован-ного формирования фазового состава и структуры плёнок на основе скуттерудита CoSb₃, осаждённых методом вакуумной конденсации, а также влияния фактора наноразмерности на их термоэлектрические свойства.
Роботу присвячено встановленню закономірностей термостимульованого формування фазового складу та структури плівок на основі скутерудиту CoSb₃, осаджених методом вакуумної конденсації, а також впливу чинника нанорозмірности на їхні термоелектричні властивості.
The authors are grateful to colleagues from Department of Surface and Interface Physics at Institute of Physics of Technische Universität Chemnitz (Germany), particularly head of the department Prof. M. Albrecht, Drs. M. Daniel and G. Beddies for the fabrication of samples, help during the investigations, and discussing the results. This work was financially supported by the German scientific exchange organization (DAAD) within the framework of the Euler program (grants No. 08/01145 and No. 50744282).
en
Інститут металофізики ім. Г.В. Курдюмова НАН України
Успехи физики металлов
Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
Изготовление наноразмерных плёнок на основе скуттерудита CoSb₃ для термоэлектрических приборов
Виготовлення нанорозмірних плівок на основі скутерудиту CoSb₃ для термоелектричних приладів
Article
published earlier
spellingShingle Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
Makogon, Yu.M.
Sidorenko, S.I.
Shkarban, R.A.
title Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
title_alt Изготовление наноразмерных плёнок на основе скуттерудита CoSb₃ для термоэлектрических приборов
Виготовлення нанорозмірних плівок на основі скутерудиту CoSb₃ для термоелектричних приладів
title_full Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
title_fullStr Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
title_full_unstemmed Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
title_short Fabrication of Nanosize Films on the Base of Scutterudite CoSb₃ for Thermoelectric Devices
title_sort fabrication of nanosize films on the base of scutterudite cosb₃ for thermoelectric devices
url https://nasplib.isofts.kiev.ua/handle/123456789/167901
work_keys_str_mv AT makogonyum fabricationofnanosizefilmsonthebaseofscutteruditecosb3forthermoelectricdevices
AT sidorenkosi fabricationofnanosizefilmsonthebaseofscutteruditecosb3forthermoelectricdevices
AT shkarbanra fabricationofnanosizefilmsonthebaseofscutteruditecosb3forthermoelectricdevices
AT makogonyum izgotovlenienanorazmernyhplenoknaosnoveskutteruditacosb3dlâtermoélektričeskihpriborov
AT sidorenkosi izgotovlenienanorazmernyhplenoknaosnoveskutteruditacosb3dlâtermoélektričeskihpriborov
AT shkarbanra izgotovlenienanorazmernyhplenoknaosnoveskutteruditacosb3dlâtermoélektričeskihpriborov
AT makogonyum vigotovlennânanorozmírnihplívoknaosnovískuteruditucosb3dlâtermoelektričnihpriladív
AT sidorenkosi vigotovlennânanorozmírnihplívoknaosnovískuteruditucosb3dlâtermoelektričnihpriladív
AT shkarbanra vigotovlennânanorozmírnihplívoknaosnovískuteruditucosb3dlâtermoelektričnihpriladív