98 results on '"Ivan Karbovnyk"'
Search Results
2. Impedance analysis of PEDOT:PSS/CNT composites below percolation threshold
- Author
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Dmytro Lukashevych, Illia Zhydenko, Halyna Klym, Dmytro Chalyy, and Ivan Karbovnyk
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Materials science ,Polymer nanocomposite ,Materials Science (miscellaneous) ,02 engineering and technology ,Carbon nanotube ,Conductivity ,010402 general chemistry ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,PEDOT:PSS ,law ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Composite material ,Nanocomposite ,Percolation threshold ,Cell Biology ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Dielectric spectroscopy ,Condensed Matter::Soft Condensed Matter ,Equivalent circuit ,0210 nano-technology ,Biotechnology - Abstract
Electrical responses of pre-percolation PEDOT:PSS polymer 30 micron thick films with incorporated single-walled carbon nanotubes were studied by means of impedance spectroscopy technique. The quantitative description of conductivity features is attempted using equivalent circuit modeling. The proposed model is applied to the experimentally investigated nanocomposite systems with different loadings of the nanofiller.
- Published
- 2021
3. Highly luminescent and electrically conductive hybrid material
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Patrizia Lamberti, T. A. Pavich, Tinatin Kuchukhidze, A. V. Kukhta, Natia Jalagonia, Alesya Paddubskaya, Ivan Karbovnyk, and Sergei A. Maksimenko
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Luminescence ,Materials science ,Materials Science (miscellaneous) ,Oxide ,Nanochemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Conductivity ,Eu complex ,Quenching ,Reduced graphene oxide ,law ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Conductive polymer ,chemistry.chemical_classification ,Graphene ,Cell Biology ,Polymer ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,chemistry ,Chemical engineering ,0210 nano-technology ,Europium ,Hybrid material ,Biotechnology - Abstract
We proposed a highly luminescent and electrically conducting polymer composite material based on polylactide acid (PLA) polymer filled with reduced graphene oxide (RGO) or graphene oxide (GO) nanoplatelets covered by organic Eu(III) complexes tris-dibenzoylmethane mono-1,10-phenanthroline europium(III) [Eu(DBM)3Phen]. No Eu(DBM)3Phen luminescence quenching by RGO and GO nanoplatelets has been observed in emission decay. Partial luminescence intensity decrease is caused by graphene nanoplatelets absorption. Conductivity of the composite film is increased by more than five orders of magnitude as compared to the pure polymer. The proposed material is suitable for 3D printing technology and wide applications in optoelectronics.
- Published
- 2021
4. Polarized photoluminescence of Alq3 thin films obtained by the method of oblique-angle deposition
- Author
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Y. Kulyk, Ivan Karbovnyk, S. Majevska, A. V. Kukhta, Y. Eliyashevskyi, V Savaryn, V. Vasilyev, V. Stybel, A Horyn, B. Turko, Andrij Kostruba, and B. Sadovyi
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Photoluminescence ,Materials science ,business.industry ,Optoelectronics ,Thin film ,business ,Oblique angle ,Deposition (chemistry) ,Atomic and Molecular Physics, and Optics - Published
- 2021
5. Low-temperature luminescence of CdI2 under synchrotron radiation
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Anatoli I. Popov, R. M. Lys, Halyna Klym, Ivan Karbovnyk, Ivan Bolesta, S. Velgosh, I. Makarenko, I.V. Kityk, Viktorija Pankratova, and Vladimir Pankratov
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010302 applied physics ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed Matter::Other ,Excitation spectra ,Doping ,Analytical chemistry ,Physics::Optics ,General Physics and Astronomy ,Synchrotron radiation ,Luminescence spectra ,Electronic structure ,01 natural sciences ,3. Good health ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Cadmium iodide ,chemistry ,Impurity ,Condensed Matter::Superconductivity ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,Luminescence - Abstract
Synchrotron radiation is applied to study visible and UV luminescence spectra and their excitation spectra of undoped as well as In and Sb doped cadmium iodide crystals at 10 K. The origin of principal luminescence bands and the role of impurities in the formation of emission centers are discussed. The luminescence properties have been explained based on the electronic structure of CdI2 crystals.
- Published
- 2020
6. The impact of temperature on electrical properties of polymer-based nanocomposites
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Illia Zhydenko, Halyna Klym, A.A Popov, Dmytro Lukashevych, Ivan Karbovnyk, Dmytro Chalyy, and Sergei Piskunov
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010302 applied physics ,chemistry.chemical_classification ,Range (particle radiation) ,Materials science ,Thin layers ,Nanocomposite ,Physics and Astronomy (miscellaneous) ,General Physics and Astronomy ,multi-walled carbon nanotubes ,Polymer ,Carbon nanotube ,7. Clean energy ,01 natural sciences ,law.invention ,polymer based nanocomposites ,chemistry ,law ,0103 physical sciences ,NATURAL SCIENCES:Physics [Research Subject Categories] ,Composite material ,010306 general physics ,low-temperature hysteresis - Abstract
This work was supported by National Research Foundation of Ukraine, project 2020.02/0217. IK would also like to thank VIAA, State Education Development Agency for Latvian state fellowship. HK would like to thank Ministry of Education and Science of Ukraine, project for young researchers No. 0119U100435. In addition, SP and AAP are thankful for financial support from Latvian Council of Science via grant lzp-2018/2-0083. HK and AAP are grateful for the support from the COST Action CA17126., The paper discusses the results of temperature studies of polymer-based nanocomposites obtained by incorporating multi-walled carbon nanotubes in thin layers of poly(3,4-ethylenedioxythophene):poly(4-styrenesulfonate), specifically focusing on interesting features in the dependencies of electrical properties across the wide range of temperatures from ambient one down to 10 K. --//-- This is the preprint version of the following article: I. Karbovnyk, H. Klym, S. Piskunov, A. A. Popov, D. Chalyy, I. Zhydenko and D. Lukashevych,The impact of temperature on electrical properties of polymer-based nanocomposites, Low Temperature Physics, 46, 1231 (2020), DOI https://doi.org/10.1063/10.0002479, which has been published in final form at https://aip.scitation.org/doi/10.1063/10.0002479., National Research Foundation of Ukraine, project 2020.02/0217; VIAA; Ministry of Education and Science of Ukraine, project for young researchers No. 0119U100435; Latvian Council of Science via grant lzp-2018/2-0083; COST Action CA17126; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART².
- Published
- 2020
7. Definition System of Human Body Position in Virtual Reality
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Roman Diachok, Halyna Klym, Ivanna Vasylchyshyn, and Ivan Karbovnyk
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- 2022
8. Modeling of Percolation Effect in Arrays of Curved Nanotubes
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Illia Zhydenko, Halyna Klym, Dmytro Chalyy, and Ivan Karbovnyk
- Published
- 2022
9. Raman spectra of vacancy-containing LiF: Predictions from first principles
- Author
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Ivan Karbovnyk, I. Makarenko, Inta Isakoviča, Anatoli I. Popov, Sergei Piskunov, and A. V. Sorokin
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Nuclear and High Energy Physics ,Materials science ,Spin states ,02 engineering and technology ,Electronic structure ,Electron ,021001 nanoscience & nanotechnology ,01 natural sciences ,Effective nuclear charge ,symbols.namesake ,Vacancy defect ,0103 physical sciences ,symbols ,Density functional theory ,Atomic physics ,010306 general physics ,0210 nano-technology ,Raman spectroscopy ,Instrumentation ,Raman scattering - Abstract
The electronic structure and Raman scattering from face-centered cubic LiF with three types of vacancies — an F-center, an F ′ -center and a vacancy without electrons ( v F ) — has been calculated by means of hybrid exchange–correlation functional within density functional theory. Our modeling predicts the effective charge of 0.87 e , 1.50 e and 0.10 e on the defect, respectively. The F-center induces two in-gap energy levels for two spin states split by 3.4 eV, while the F ′ -center and the v F induce a single in-gap level 3.8 eV and 2.9 eV below the bottom of conduction band, respectively. The calculated Raman spectra are thoroughly discussed and are found to match well the earlier experimental data. Several peaks are found to shift consistently with the increase of the charge on the vacancy at the rate of about - 35 cm - 1 / e .
- Published
- 2020
10. Poly(3,4-ethylenedioxythiophene)/carbon-based nanocomposite for gas sensing
- Author
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Yu. I. Olenych, I. B. Olenych, Yu. Yu. Horbenko, B. R. Tsizh, Ivan Karbovnyk, and Olena Aksimentyeva
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Nanocomposite ,Materials science ,Graphene ,Oxide ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Electrical resistivity and conductivity ,law ,General Materials Science ,0210 nano-technology ,Carbon ,Poly(3,4-ethylenedioxythiophene) - Abstract
In this study, we have manufactured sensory films based on poly(3,4-ethylenedioxythiophene)/carbon nanotubes/reduced graphene oxide nanocomposite. The charge transport in obtained films was analyze...
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- 2020
11. Alignment of luminescent liquid crystalline molecules on modified PEDOT:PSS substrate
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Sergei A. Maksimenko, Halyna Klym, Konstantin M. Degtyarenko, I. N. Kukhta, A. V. Kukhta, Andriy Luchechko, B. Sadovyi, T. N. Kopylova, B. Turko, A. Lugovskii, and Ivan Karbovnyk
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Conductive polymer ,Materials science ,Materials Science (miscellaneous) ,Substrate (chemistry) ,Nanochemistry ,02 engineering and technology ,Cell Biology ,Chemical vapor deposition ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,PEDOT:PSS ,Liquid crystal ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Thin film ,0210 nano-technology ,Luminescence ,Biotechnology - Abstract
Aligned organic thin films with polarized luminescence are obtained by means of the slow vapor deposition of fluorescent blue emitting organic liquid crystalline dipolar molecules, 4-(n-penthyl)-3-chloro-4‴-trifluoromethoxy-[1,1ʹ,4ʹ,1ʺ,4ʺ,1‴-quaterphenyl] (M-BLUE), and red emitting molecules, 4-(dicyanomethylene)-2-(4-amylcyclohexyl)-6[4-(dimethylaminostyryl)]-4H-pyran molecule (M-RED), on the surface of the rubbed conducting polymer (PEDOT:PSS). The polarization degree of M-BLUE thin film was found to be 31%, and for M-RED it is 48%. Essential luminescence quenching by PEDOT:PSS was observed. Strong blue shift of M-RED luminescence on PEDOT:PSS substrate is caused probably because of strong interaction between these counterparts.
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- 2020
12. Positron Annihilation Lifetime Spectroscopy Insight on Free Volume Conversion of Nanostructured MgAl2O4 Ceramics
- Author
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Halyna Klym, Ivan Karbovnyk, Sergei Piskunov, and Anatoli I. Popov
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010302 applied physics ,Positron trapping ,General Chemical Engineering ,Free-volume defects ,Positron annihilation ,positron annihilation ,nanopores ,positronium decay ,02 engineering and technology ,nanostructured ceramics ,free-volume defects ,positron trapping ,021001 nanoscience & nanotechnology ,Positronium decay ,7. Clean energy ,01 natural sciences ,Nanopores ,Chemistry ,0103 physical sciences ,NATURAL SCIENCES [Research Subject Categories] ,General Materials Science ,0210 nano-technology ,Nanostructured ceramics ,QD1-999 - Abstract
H.K. and A.I.P. are grateful for the support from the COST Action CA17126. H.K. was also supported by the Ministry of Education and Science of Ukraine (project for young researchers No. 0119U100435). In addition, I.K. and H.K. were also supported by the National Research Foundation of Ukraine via project 2020.02/0217, while the research of A.I.P. was funded by the Latvian research council via the Latvian National Research Program under the topic ?High-Energy Physics and Accelerator Technologies?, Agreement No: VPP-IZM-CERN-2020/1-0002. In addition, the research of A.I.P. has been supported by the Latvian-Ukrainian Grant LV-UA/2021/5. The Institute of Solid State Physics, University of Latvia (Latvia) as the Centre of Excellence has received funding from the European Union?s Horizon 2020 Framework Programme H2020-WIDESPREAD01-2016-2017- Teaming Phase2 under grant agreement No. 739508, project CAMART2., Herein we demonstrate the specifics of using the positron annihilation lifetime spectroscopy (PALS) method for the study of free volume changes in functional ceramic materials. Choosing technological modification of nanostructured MgAl2 O4 spinel as an example, we show that for ceramics with well-developed porosity positron annihilation is revealed through two channels: positron trapping channel and ortho-positronium decay. Positron trapping in free-volume defects is described by the second component of spectra and ortho-positronium decay process by single or multiple components, depending on how well porosity is developed and on the experimental configuration. When using proposed positron annihilation lifetime spectroscopy approaches, three components are the most suitable fit in the case of MgAl2 O4 ceramics. In the analysis of the second component, it is shown that technological modification (increasing sintering temperature) leads to volume shrinking and decreases the number of defect-related voids. This process is also accompanied by the decrease of the size of nanopores (described by the third component), while the overall number of nanopores is not affected. The approach to the analysis of positron annihilation lifetime spectra presented here can be applied to a wide range of functional nanomaterials with pronounced porosity. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Published under the CC BY 4.0 license., European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD01-2016-2017-Teaming Phase2 739508; Latvian National Research Program VPP-IZM-CERN-2020/1-0002; Latvian Science Council; National Research Foundation of Ukraine 2020.02/0217; European Cooperation in Science and Technology CA17126; National Research Foundation of Korea; Latvijas Universitate; Institute of Solid State Physics, Chinese Academy of Sciences; Ministry of Education and Science of Ukraine 0119U100435; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
- Published
- 2021
13. Optical properties of composite structure based on ZnO microneedles and Alq3 thin film
- Author
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Roman Serkiz, V. Vasilyev, P.K. Khanna, Y. Kulyk, A. M. Kostruba, Halyna Klym, Ivan Karbovnyk, B. Sadoviy, A. V. Kukhta, B. Turko, and Andriy Luchechko
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Photoluminescence ,Materials science ,business.industry ,Composite number ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Composite structure ,Excited state ,OLED ,Molecule ,Optoelectronics ,Thin film ,Electrical and Electronic Engineering ,business ,Laser beams - Abstract
The composite material based on ZnO microneedles and Alq3 thin film has been obtained. The photoluminescence study shows a tenfold enhancement in the band-edge UV emission (390 nm) of ZnO microneedles and 2 × enhancement in visible emission of the hybrid composite, when excited by 266 nm laser beam. This enhancement can be explained by the interaction between ZnO and Alq3 molecules and the energy transfer from ZnO to Alq3 molecule. Discussed composite structures can find interesting applications as emitting layers in OLED devices.
- Published
- 2021
14. Positron Annihilation Lifetime Spectroscopy Insight on Free Volume Conversion of Nanostructured MgAl
- Author
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Halyna, Klym, Ivan, Karbovnyk, Sergei, Piskunov, and Anatoli I, Popov
- Subjects
positron annihilation ,nanopores ,positronium decay ,positron trapping ,nanostructured ceramics ,free-volume defects ,Article - Abstract
Herein we demonstrate the specifics of using the positron annihilation lifetime spectroscopy (PALS) method for the study of free volume changes in functional ceramic materials. Choosing technological modification of nanostructured MgAl2O4 spinel as an example, we show that for ceramics with well-developed porosity positron annihilation is revealed through two channels: positron trapping channel and ortho-positronium decay. Positron trapping in free-volume defects is described by the second component of spectra and ortho-positronium decay process by single or multiple components, depending on how well porosity is developed and on the experimental configuration. When using proposed positron annihilation lifetime spectroscopy approaches, three components are the most suitable fit in the case of MgAl2O4 ceramics. In the analysis of the second component, it is shown that technological modification (increasing sintering temperature) leads to volume shrinking and decreases the number of defect-related voids. This process is also accompanied by the decrease of the size of nanopores (described by the third component), while the overall number of nanopores is not affected. The approach to the analysis of positron annihilation lifetime spectra presented here can be applied to a wide range of functional nanomaterials with pronounced porosity.
- Published
- 2021
15. Effect Changing of Nanopore Volumes in MgAl2O3 Ceramics under the Influence of Water
- Author
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Halyna Klym, Yuriy Kostiv, and Ivan Karbovnyk
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Nanopore ,Positron ,Materials science ,Adsorption ,Chemical engineering ,Economies of agglomeration ,visual_art ,Desorption ,visual_art.visual_art_medium ,Grain boundary ,Ceramic ,Spectroscopy - Abstract
The influence of adsorbed water on the change of free volume and nanopores in the MgAl 2 O 4 ceramics sintered at 1100 °C for 2 $h$ been studied using positron annihilation lifetime method. It is shown that after immersion of ceramics in water the positron and ortho-positronium trapping occurs more intensely. After drying of ceramic part of the water remains, as evidenced by the parameters of the third component of the annihilation spectrum. It has been established that adsorption processes in MgAl 2 O 4 ceramics lead to the fragmentation of nanopores, while desorption causes their agglomeration
- Published
- 2021
16. Features of changes in the electrical resistance of p-Si crystals under the action of an elastic one-axial mechanical load and a magnetic field
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R. I. Didyk, B. Pavlyk, D. P. Slobodzyan, R. M. Lys, Josyp Shykorjak, Ivan Karbovnyk, and M. O. Kushlyk
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Materials science ,Mechanical load ,Silicon ,Condensed matter physics ,Materials Science (miscellaneous) ,chemistry.chemical_element ,02 engineering and technology ,Cell Biology ,Penetration (firestop) ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Spectral line ,0104 chemical sciences ,Magnetic field ,chemistry ,Electrical resistance and conductance ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Sheet resistance ,Biotechnology - Abstract
In thе work, changes in the surface electrical resistance of p-Si crystals were investigated under the simultaneous action of the magnetic field and elastic uniaxial deformation. It was established that a sharp decrease (leap) of resistance occurs at the moment of transition from compression to unclamping at a magnitude of a mechanical load exceeding 18 MPa. Such a leap of resistance is not observed under the elastic uniaxial deformations, which do not exceed 14 MPa. This can be explained by the fact that due to the deeper and more prolonged penetration of the dislocation loops, and the corresponding increase in their length, they accumulate a significant number of charged defects that remain unplaced at the beginning of the release (reduction of the field of mechanical stress). A fluctuation of the resistance value in the direction of increase or towards the reduction occurs in the magnetic field. The diffusion of magnetically sensitive defects into the near-surface region can be explained by the repetition of the processes described in time. In a deformed crystalline lattice, diffusion processes occur more rapidly, which increases the frequency of oscillations of the resistance value. By investigating the IR absorption spectra of experimental samples, it was shown that the decay of defects on the surface (111) of p-Si crystals occurs during a long-term action (288 h) of a constant magnetic field (B = 0.354 T). Such defects are hydrogen-containing and oxygen-containing complexes (Si–O–Si, Si–Si, Si–H2, Si–C, O–Si–O, Si–O–C, Si–CH3, H–OH, H2O, Si–OH). This leads to an increase in the surface resistance of the experimental samples of silicon.
- Published
- 2019
17. Melting of tetrahedrally bonded semiconductors: 'anomaly' of the phase diagram of GaN?
- Author
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S. Porowski, Sylwester J. Rzoska, I. Grzegory, Stanislaw Gierlotka, I. A. Petrusha, Ivan Karbovnyk, B. Sadovyi, Vladimir Z. Turkevich, and D. A. Stratiichuk
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010302 applied physics ,Materials science ,Condensed matter physics ,business.industry ,Melting temperature ,Coordination number ,Liquid phase ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Inorganic Chemistry ,Semiconductor ,0103 physical sciences ,Materials Chemistry ,Low density ,Anomaly (physics) ,0210 nano-technology ,business ,Phase diagram - Abstract
In this paper we initiate further discussion on phase diagrams and structural transitions in tetrahedrally bonded semiconductors with particular emphasis on GaN. Comprehensive experimental data and the most important theoretical predictions are comprised in an effort to bring up a generalized universal scheme that explain melting that may or may not be accompanied by the change of the coordination number. The scheme considers the “anomalous” melting temperature dependence on pressure for GaN. Principal possibility of GaN melting into low density semiconducting liquid is demonstrated and challenges on the way to experimental observation of such liquid phase are disputed. Prospects of future experiments that can provide reliable information on the nature of atomic bonding for different GaN phases are laid out.
- Published
- 2019
18. Extended Positron‐Trapping Defects in the Eu 3+ ‐Doped BaGa 2 O 4 Ceramics Studied by Positron Annihilation Lifetime Method
- Author
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Halyna Klym, Ivan Karbovnyk, Andriy Luchechko, Yuriy Kostiv, and Anatoli I. Popov
- Subjects
Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2022
19. On the Crystallization Ability of 80GeSe2-20Ga2Se3 Glasses
- Author
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Ivanna Vasylchyshyn, Ivan Karbovnyk, and Halyna Klym
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Diffraction ,Materials science ,Annealing (metallurgy) ,Chalcogenide ,Nanoparticle ,Thermal treatment ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Phase (matter) ,Crystallite ,Crystallization - Abstract
Peculiarities of crystallization behavior of the 80GeSe2-20Ga2Se3 chalcogenide glasses caused by thermal treatment at 380 °C for 10, 25, 50, 80 and 100 h were studied using X-ray diffraction method. It is shown that crystallization processes indicate on the formation of GeGa4Se8, Ga2Se3 and GeSe2 crystallizes in nanoparticle form in the inner structure of the studied glasses. Crystallites are formed in different modifications: GeGa4Se phase of low-temperature and high-temperature modifications as well as α, γ-modification of Ga2Se3 phases. The most significant changes in the 80GeSe2-20Ga2Se3 glasses occur after thermal treatment for 25 and 50 h. Following crystallization for 80 and 100 h does not reflect the increase in intensity which indicate the further formation of phases in the inner structure of glasses.
- Published
- 2021
20. Grain-Porous Investigations of the Cu0.4Ni0.4Co0.4Mn1.8O4 Ceramics
- Author
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Dmytro Lukashevych, Halyna Klym, Ivan Karbovnyk, and Ivan Hadzaman
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010302 applied physics ,Materials science ,Spinel ,Analytical chemistry ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Nanopore ,Agglomerate ,Specific surface area ,visual_art ,Phase (matter) ,0103 physical sciences ,engineering ,visual_art.visual_art_medium ,Ceramic ,0210 nano-technology ,Porosity - Abstract
Phase compositions, microstructural properties and pore size distribution in the Cu 0.4 Ni 0.4 Co 0.4 Mn 1.8 O 4 ceramics in micro and macro modifications were investigated. It is shown that the micro and macro modified Cu 0.4 Ni 0.4 Co 0.4 Mn 1.8 O 4 ceramics are single-phase (contains only the main cubic spinel phase with cell parameter of 8.36504 (19) Aand 8.36505 (20) A for the micro and macro modified Cu 0.4 Ni 0.4 Co 0.4 Mn 1.8 O 4 , respectively). Different modifications of ceramics are displayed in the size and shape of pores. In micro modified Cu 0.4 Ni 0.4 Co 0.4 Mn 1.8 O 4 ceramics there is a more intensive growth of the contact area between the grains. increases the specific surface area. The grain is combined into agglomerates. One peak with nanopore with radius centered near ~ 2 nm is peculiar to macro modified Cu 0.4 Ni 0.4 Co 0.4 Mn 1.8 O 4 ceramics. Double maximum is characteristic to micro ceramics (~2.3 and 5.5 nm).
- Published
- 2020
21. Electrical Behavior of Single/Multi-Walled Carbon Nanotubes Composites
- Author
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Dmytro Lukashevych, Halyna Klym, Ivan Karbovnyk, Dmytro Chalyy, and Illia Zhydenko
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Arrhenius equation ,chemistry.chemical_classification ,Nanotube ,Materials science ,Composite number ,Doping ,02 engineering and technology ,Polymer ,Carbon nanotube ,Atmospheric temperature range ,Conductivity ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Condensed Matter::Materials Science ,symbols.namesake ,chemistry ,law ,symbols ,Composite material ,0210 nano-technology - Abstract
Peculiarities of electrical properties of compound materials fabricated by introduction of single- and multiwalled carbon nanotubes with high level of purity into polymer host matrix were studied. Detailed investigation of lateral resistances of the prepared samples in the range of temperatures from 50 to 200 K were performed. Analysis of the conductivity mechanisms in this temperature range was performed by applying Arrhenius equation-based models. Temperature dependencies of lateral resistance were fitted to extract respective activation energies. Distinctions between fabricated specimens reinforced with multi-walled nanotubes and those doped by single-walled carbon nanotubes were demonstrated. It is concluded that composites with multiwalled carbon nanotubes generally exhibit lower resistances as compared to their single-walled counterpart.
- Published
- 2020
22. LabVIEW-based Automated Setup for Interferometric Refractive Index Probing
- Author
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Nazariy Andrushchak and Ivan Karbovnyk
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Physics - Instrumentation and Detectors ,Computer science ,Instrumentation ,Reference data (financial markets) ,FOS: Physical sciences ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,Automation ,Optics ,Data acquisition ,Software ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,business.industry ,Michelson interferometer ,Signal Processing, Computer-Assisted ,020206 networking & telecommunications ,Instrumentation and Detectors (physics.ins-det) ,Computer Science Applications ,Biophotonics ,Refractometry ,Medical Laboratory Technology ,Interferometry ,Physics - Data Analysis, Statistics and Probability ,business ,Refractive index ,Data Analysis, Statistics and Probability (physics.data-an) - Abstract
In the paper, we explain an automated LabVIEW-controlled setup that enables interferometric measurement of refractive indices in crystalline materials using a laser light source. The setup combines a mechanical system, a microcomputer-controlled gearless drive, a Michelson interferometer, an optical detector, a data acquisition system, and a LabVIEW virtual instrument for an accurate nondestructive determination of the refractive index of given plane-parallel samples. We explain the concept, implementation, and hardware/software peculiarities of the developed system. Test experiments on different crystals yielded results that are in good agreement with available reference data. The range of potential applications of the proposed setup extends from fundamental optical research to biophotonics instrumentation, where efficient delivery of light is of crucial importance and reliable automated probing tools are needed for optical component characterization.
- Published
- 2020
23. Effect of elastic deformation and the magnetic field on the electrical conductivity of p-Si crystals
- Author
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J. Shykorjak, B. Pavlyk, R. I. Didyk, R. M. Lys, and Ivan Karbovnyk
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010302 applied physics ,Materials science ,Condensed matter physics ,Materials Science (miscellaneous) ,02 engineering and technology ,Cell Biology ,Activation energy ,Conductivity ,equipment and supplies ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Magnetic field ,Crystal ,Electrical resistivity and conductivity ,0103 physical sciences ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Dislocation ,Deformation (engineering) ,0210 nano-technology ,human activities ,Sheet resistance ,Biotechnology - Abstract
It is shown that at a deformation rate of 0.41 kg/min, the characteristic feature of the dependence of the surface resistance of the p-Si sample on the magnitude of its elastic deformation (R(σ)) is the reduction of the resistance during compression and unclamping. With the increase in the number of “compression-unclamping” cycles, the difference between the positions of the compression and unclamping curves decreases. The transformation of two types of magnetically sensitive defects occurs under the impact of a magnetic field on p-Si crystals. The defects are interrelated with two factors that cause the mutually opposite influence on the conductivity of the crystal. The first factor is that the action of the magnetic field decreases the activation energy of the dislocation holders, which leads to an increase in the electrical conductivity of the sample. The second factor is that due to the decay of molecules of oxygen-containing impurities in the magnetic field, the stable chemisorption bonds appear in the crystal that leads to a decrease in its conductivity. If the sample stays in the magnetic field for a long time, the one or the other mechanism predominates, causing a slow growth or decrease in resistance around a certain (averaged) value. Moreover, the frequency of such changes is greater in the deformed sample. The value of the surface resistance of p-Si samples does not change for a long time without the influence of the magnetic field.
- Published
- 2018
24. Effect of non-resonant polarized laser irradiation on the formation of nanostructured organic thin films
- Author
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I. N. Kukhta, A. V. Kukhta, Halyna Klym, M. I. Taoubi, A. Lugovskii, B. Turko, Marcin Sarzyński, Ivan Karbovnyk, Andriy Luchechko, and B. Sadovyi
- Subjects
Materials science ,Materials Science (miscellaneous) ,Physics::Optics ,Nanochemistry ,02 engineering and technology ,Chemical vapor deposition ,010402 general chemistry ,Photochemistry ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,law ,Physics::Atomic Physics ,Irradiation ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Thin film ,Spectroscopy ,Cell Biology ,021001 nanoscience & nanotechnology ,Laser ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Absorption band ,0210 nano-technology ,Luminescence ,Biotechnology - Abstract
Nanostructured organic thin film with polarized luminescence is obtained by means of the vapor deposition of fluorescent liquid crystalline dipolar molecules in the presence of polarized laser irradiation outside the absorption band. It was shown that irradiation of molecules by non-resonant polarized laser beam during deposition strongly decreases the formation of aggregated molecules that is confirmed by atomic force microscopy, fluorescent microscopy and luminescent spectroscopy.
- Published
- 2018
25. Modeling and quantitative analysis of connectivity and conductivity in random networks of nanotubes
- Author
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R. M. Lys, Yuriy Kostiv, Oleksandr Berezko, Halyna Klym, Andriy Stelmashchuk, and Ivan Karbovnyk
- Subjects
Nanotube ,Materials science ,Energy Engineering and Power Technology ,02 engineering and technology ,Conductivity ,01 natural sciences ,Industrial and Manufacturing Engineering ,Condensed Matter::Materials Science ,Management of Technology and Innovation ,0103 physical sciences ,Electronic engineering ,Statistical physics ,Electrical and Electronic Engineering ,010302 applied physics ,Nanocomposite ,Applied Mathematics ,Mechanical Engineering ,Percolation threshold ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Thermal conduction ,Aspect ratio (image) ,Computer Science Applications ,Control and Systems Engineering ,Percolation ,Representative elementary volume ,0210 nano-technology - Abstract
The work describes the framework that allows performing a computer simulation of complex random networks of conducting nanotubes embedded in the dielectric medium. The representative volume element filled with a large number of interconnected nanotubes is modeled and the tunneling conduction mechanism between adjacent tubes is considered. The principal goal is to develop a computational approach for the threedimensional multielement structure simulation, which will be relatively simple, yet capable of producing realistic results. The connectivity formation processes among nanotubes in random nanotube networks are studied using the elements of graph theory. All stages of the modeling process are discussed in details. The system conductivity model with taking into account the tunnel effect and intrinsic nanotube conductivities is formulated. The random resistor model is used to calculate the total equivalent conductivity of the network. The results of the computer experiments on electrical conductivity simulations for different systems are presented. The dependencies of the electrical conductivity of nanotube networks in the insulating medium on the concentration of nanotubes, geometric parameters and properties of tunneling conductivity between individual tubes are investigated. It is found that the percolation threshold corresponds to the nanotube loading of 0.5 % when the aspect ratio of nanotubes is 160. Nonlinear dependence between the aspect ratio and the percolation threshold was established. The analysis of computational complexity and calculation time is performed for quadcore computing systems. Computer experiments carried out in a systematic fashion within the proposed framework can be useful when designing novel CNTpolymer composites for state of the art electronic applications. By following the predictions of the proposed model, tailoring of electrical properties of such composites can be made easier when adjusting the parameters of nanotubes and their concentration during the fabrication of the nanocomposite samples.
- Published
- 2017
26. Structural Properties of Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions
- Author
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Andriy Luchechko, Ivan Karbovnyk, Bohdan Sadovyi, Yuriy Kostiv, Halyna Klym, and Oksana Kravets
- Subjects
Crystallography ,Materials science ,Scanning electron microscope ,visual_art ,Phase (matter) ,Doping ,visual_art.visual_art_medium ,Sintering ,Grain boundary ,Ceramic ,Crystallite ,Microstructure - Abstract
Polycrystalline BaGa 2 O 4 ceramics doped with Eu3+ ions (1,3 and 4 mol%) were obtained using solid state sintering. Structural properties of these ceramics were investigated using scanning electron microscopy and X-ray diffraction methods. It is shown that BaGa 2 O 4 ceramics are characterized by advanced structure of grains, grain boundaries and pores. Base undoped BaGa 2 O 4 ceramics contain three phases, samples with 3 and 4 mol% of Eu2o3 are the mixtures of two phases (BaGa 2 O 4 and EU 3 GaO 6 ), while BaGa 2 O 4 ceramics with 1 mol% of Eu2o3 contain only one (Ba,Eu)Ga 2 O 4 phase of own structural type.
- Published
- 2019
27. Study of Crystallization Ability of Ge-Ga-S Glasses by X-ray Diffraction and Calorimetric Methods
- Author
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Andrzej Kozdras, Dmytro Lukashevych, Halyna Klym, and Ivan Karbovnyk
- Subjects
Diffraction ,Crystallography ,chemistry.chemical_compound ,Materials science ,chemistry ,law ,Chalcogenide ,Phase (matter) ,X-ray crystallography ,Crystallization ,law.invention - Abstract
Crystallization ability of the 80GeS 2 -20Ga 2 S 3 , 82GeS 2 -18Ga 2 S 3 and 84GeS 2 -16Ga 2 S 3 chalcogenide glasses were studied using X-ray diffraction and calorimetric methods. It is shown that structure of these glasses is characterized by short range ordering. It is established that Ga 2 S 3 and GeS 2 phases can be crystallized in Ge-Ga-S system.
- Published
- 2019
28. Multichannel Positron Trapping Models for Describing Transformation of Free Volumes in Nanostructured Functional Materials
- Author
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Dmytro Lukashevych, Dmytro Chalyy, Ivan Karbovnyk, Oleh Shpotyuk, and Halyna Klym
- Subjects
Annihilation ,Materials science ,Chalcogenide ,Spinel ,Trapping ,engineering.material ,Positronium ,Nanopore ,chemistry.chemical_compound ,Positron ,chemistry ,Chemical physics ,visual_art ,visual_art.visual_art_medium ,engineering ,Ceramic - Abstract
Multichannel positron and positron- positronium trapping models were developed to study of free volumes in functional nanostructured materials. Proposed model applied to investigation of free volumes and/or nanopores in such nanostructured functional materials as Ga- Ga-Se/s chalcogenide glasses and MgAl 2 O 4 spinel ceramics.
- Published
- 2019
29. Development and characterization of a new class of crystalline nanocomposites with tailored anisotropy for micro- and nanoelectronics
- Author
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Volodymyr Adamiv, Yaroslav Shchur, Ivan Karbovnyk, Anatoliy Andrushchak, O. Buryy, and Galyna Klym
- Subjects
chemistry.chemical_compound ,Nanocomposite ,Materials science ,chemistry ,Nanoelectronics ,Nanoporous ,Anodizing ,Aluminium oxide ,Nanotechnology ,Anisotropy ,Characterization (materials science) - Abstract
We report on the development and research of a new class of crystalline nanocomposites with tailored anisotropy for micro- and nanoelectronics, targeting applications in telecommunication networks working in optical and subterahertz wave ranges. Different induced optical effects in mentioned materials are analyzed by extreme surfaces method that allows to determine the global maxima of a specific interaction. The results are obtained for the family of novel nanocomposite materials based on the host nanoporous matrices from silica (SiO 2 ) and anodized aluminium oxide (AAO) filled with nanostructured KDP, ADP, TGS, Ba(NO 3 ) 2 and KB-5 crystals. Changes due to various pore diameters, inter-pore spacing and morphology are analyzed.
- Published
- 2019
30. Degradation Kinetics in Cu0.1Ni0.1Co1.6Mn1.2O4-based ceramic materials
- Author
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Yuriy Kostiv, Halyna Klym, Ivan Karbovnyk, and Dmytro Lukashevych
- Subjects
Materials science ,Chemical engineering ,Degradation kinetics ,visual_art ,Kinetics ,visual_art.visual_art_medium ,Relaxation (physics) ,Degradation (geology) ,Ceramic - Abstract
Degradation kinetics in thick films based on Cu 0.1 Ni 0.1 Co 1.6 Mn 1.2 O 4 ceramics at temperature of 170 oC have been investigated. Analytical description of processes in these materials was performed using relaxation functions. It is shown, that studied degradation kinetics are adequately described by compression-exponential relaxation function.
- Published
- 2019
31. Mechanisms of Thermally-induced Degradation Kinetics in Thick Films Based on Cu0.1Ni0.1Co1.6Mn1.2O4 Ceramics
- Author
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Halyna Klym, Ivan Karbovnyk, Dmytro Lukashevych, and Anatoliy Andrushchak
- Subjects
Materials science ,Chemical engineering ,Degradation kinetics ,visual_art ,Kinetics ,visual_art.visual_art_medium ,Degradation (geology) ,Relaxation (physics) ,Ceramic - Abstract
Mechanism of thermo-induced degradation kinetics in thick films based on Cu 0.1 Ni 0.1 Co 1.6 Mn 1.2 O 4 ceramics at temperature of 170°C have been investigated. Analytical description of processes in these materials was performed using relaxation functions. It is shown, that studied degradation kinetics are adequately described by compression-exponential relaxation function.
- Published
- 2019
32. Nanostructured Ceramic-Based Sensors for Portable Electronic System of Microclimate Monitoring
- Author
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Halyna Klym, Roman Dunets, Ivanna Vasylchyshyn, Ivan Karbovnyk, Leonid Berezko, and Volodymyr Gryga
- Subjects
Materials science ,business.industry ,Arduino ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,Android application ,Ceramic ,business ,Monitoring and control ,Temperature measurement ,Electronic systems - Abstract
The nanostructured humidity-sensitive sensors based on MgAl 2 O 4 ceramics in bulk performance and temperature-sensitive multilayered thick-film sensors of different design based on semiconducting Cu 0.1 Ni 0.1 Co 1.6 Mn 1.2 O 4 and Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramics were fabricated and studied. It is shown that temperature-sensitive thick-film sensors possess sensitivity in the region of 298…358 K and humidity-sensitive sensors are sensitive in the region of 30…98 %. Designed sensors were used in the portable system realized on Arduino for monitoring and control of microclimate parameters. Obtained system were tested using Android application.
- Published
- 2019
33. Topology and Fractal Dimension of Nanocomposite Metal-Dielectric Films
- Author
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Oleksii Kushnir, Ivan Bolesta, Ivan Karbovnyk, Halyna Klym, Serhiy Velhosh, and I. N. Rovetskii
- Subjects
Condensed Matter::Materials Science ,Nanocomposite ,Materials science ,Fractal ,Condensed Matter::Superconductivity ,Phase (matter) ,Surface roughness ,Physics::Optics ,Substrate (electronics) ,Dielectric ,Composite material ,Fractal dimension ,Topology (chemistry) - Abstract
Surface topology of silver and gold ultrathin films is studied by means of atomic force microscopy. Films under study comprise metallic phase and insulating (voids) phase, therefore can be considered as metal-dielectric composites. Principal parameters of such structures are estimated depending on film thickness and substrate temperatures. Different types of fractal dimension are determined.
- Published
- 2019
34. SEM and Electrical Studies of Carbon Nanotube Reinforced PEDOT:PSS Layers
- Author
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Halyna Klym, Ivan Bolesta, Yuri Olenych, Dmytro Lukashevych, Ivan Karbovnyk, Dmytro Chalyy, and Illia Zhydenko
- Subjects
010302 applied physics ,chemistry.chemical_classification ,Range (particle radiation) ,Materials science ,Nanocomposite ,Scanning electron microscope ,02 engineering and technology ,Carbon nanotube ,Polymer ,Conductivity ,021001 nanoscience & nanotechnology ,01 natural sciences ,law.invention ,Condensed Matter::Soft Condensed Matter ,Condensed Matter::Materials Science ,chemistry ,PEDOT:PSS ,law ,0103 physical sciences ,Composite material ,0210 nano-technology - Abstract
Nanocomposite layers of PEDOT:PSS polymer which incorporate randomly dispersed carbon nanotubes were thoroughly examined by means of high-resolution scanning electron microscopy and subjected to electrical studies at different frequencies in a wide range of temperatures. Comparison between the performance of pure PEDOT:PSS layers, layers reinforced with single-walled nanotubes and those reinforced with multi-walled nanotubes is made.
- Published
- 2019
35. Microstructural Peculiarities Caused by Annealing in the Temperature-Sensitive Thick Films Based on Cu0.1Ni0.1Co1.6Mn1.2O4 Ceramics
- Author
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Halyna Klym, Ivan Hadzaman, and Ivan Karbovnyk
- Subjects
010302 applied physics ,Materials science ,Annealing (metallurgy) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Nanoelectronics ,Electrical resistance and conductance ,visual_art ,0103 physical sciences ,visual_art.visual_art_medium ,Temperature sensitive ,Grain boundary ,Ceramic ,Composite material ,0210 nano-technology ,Contact area - Abstract
Microstructural peculiarities in comparison with electrical properties in the temperature-sensitive thick films based on Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics before and after annealing (ageing test at 170 oC for 500 h) are investigated. It is shown that annealing of thick films results in diffusion of Ag from contact area in region of grain boundaries. Obtained thick films with stabile electrical properties can be used as temperature-sensitive elements micro- and nanoelectronics.
- Published
- 2019
36. Nanoporous characterization of modified humidity-sensitive MgO-Al 2 O 3 ceramics by positron annihilation lifetime spectroscopy method
- Author
-
Halyna Klym, Ivanna Vasylchyshyn, Ivan Karbovnyk, Adam Ingram, Anatoli I. Popov, and Ivan Hadzaman
- Subjects
010302 applied physics ,Materials science ,Nanoporous ,Humidity ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Characterization (materials science) ,Chemical engineering ,visual_art ,0103 physical sciences ,visual_art.visual_art_medium ,Ceramic ,0210 nano-technology ,Spectroscopy ,Positron annihilation - Abstract
The work was supported by the Ukrainian Ministry of Education and Science. H. Klym thanks Prof. O. Shpotyuk for the fruitful discussion., Investigation of nanopores in the humidity-sensitive MgO-Al2O3 ceramics modified at 1100°C for 2 hours was performed using positron annihilation lifetime spectroscopy method. Lifetimes of the third and fourth components of positron annihilation lifetime spectra obtained by four-component fitting procedure were used for calculation of nanopores radii. Transformation in free volumes was studied in ceramics after drying and exposure to water vapor. It is established that the lifetime of the third component decreases and the intensity of this component increases in ceramics exposed to water vapor reflecting ortho-positronium decay in nanopores simultaneously with annihilation in water bubbles. The characteristics of the fourth component (lifetime and intensity) decrease in ceramics exposed to water vapor reflecting ortho-positronium trapping in free-water volume of nanopores. Final drying of the MgO-Al2O3 ceramics results in returning of ortho-positronium lifetimes and intensities to the initial values confirming good desorption of water from nanopores of ceramics., Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²
- Published
- 2019
- Full Text
- View/download PDF
37. Influence of CsCl addition on the nanostructured voids and optical properties of 80GeS2-20Ga2S3 glasses
- Author
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Halyna Klym, Adam Ingram, Oleh Shpotyuk, and Ivan Karbovnyk
- Subjects
010302 applied physics ,Void (astronomy) ,Supersaturation ,Materials science ,Chalcogenide ,Organic Chemistry ,Doping ,Mineralogy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Ion ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Chemical physics ,0103 physical sciences ,Glassy matrix ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy ,Positron annihilation - Abstract
The influence of CsCl content on the void evolution in (80GeS2-20Ga2S3)100-x(CsCl)x, x = 0; 5; 10; 15, chalcogenide glasses and changes of the optical response of these glasses due to CsCl addition are investigated. It is shown that structural agglomeration of voids occurs at addition and increasing of CsCl amount in base glasses. Supersaturation of GeS2-Ga2S3-CsCl glasses by CsCl results in the contraction of void volumes in (80GeS2-20Ga2S3)85(CsCl)15. By applying positron-positronium decomposition algorithm it was established that CsCl not only transforms voids in glass, but also forms new positron-trapping sites in Ge-Ga-S glassy matrix. Therefore, CsCl addition results in the shift of fundamental transmission edge in the visible region. It is shown that doping by larger concentrations of CsCl may lead to “supersaturation” of base glasses and that adding 10 mol% of CsCl is apparently an optimal doping level in view of further modification of glasses with rare-earth ions.
- Published
- 2016
38. Influence of crystallization front direction on the Mg-related impurity centers incorporation in bulk GaN:Mg grown by HNPS method
- Author
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M. Panasyuk, V. P. Rudyk, M. Amilusik, Elzbieta Litwin-Staszewska, Izabella Grzegory, Ivan Karbovnyk, Michal Bockowski, M. Fijalkowski, B. Sadovyi, V. B. Kapustianyk, S. Porowski, and V. Tsybulskyi
- Subjects
Materials science ,Photoluminescence ,Pl spectra ,Gallium nitride ,02 engineering and technology ,01 natural sciences ,Blue band ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,Impurity ,law ,0103 physical sciences ,High nitrogen ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Crystallization ,010306 general physics ,Spectroscopy ,Organic Chemistry ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Crystallography ,chemistry ,0210 nano-technology - Abstract
We studied the incorporation of Mg-related impurity centers in GaN crystals depending on the direction of the crystallization front. Two series of GaN crystals – (i) undoped and (ii) Mg-doped – were grown by High Nitrogen Pressure Solution (HNPS) method under otherwise identical conditions. Each series contained four samples with ( 10 1 ¯ 0 ) , ( 11 2 ¯ 0 ) , ( 20 2 ¯ 1 ¯ ) and ( 20 2 ¯ 1 ) orientations. The low-temperature photoluminescence (PL) spectroscopy was used for characterization of the obtained crystals. The observed differences in the PL spectra of GaN:Mg crystals suggested that Mg incorporation in GaN grown by HNPS method depends considerably on the orientation of crystallization front. The concentration of Mg impurity incorporated into the GaN crystals subsequently increases for the following sequence of planes: ( 10 1 ¯ 0 ) , ( 11 2 ¯ 0 ) , ( 20 2 ¯ 1 ¯ ) and ( 20 2 ¯ 1 ) . For ( 10 1 ¯ 0 ) , ( 11 2 ¯ 0 ) and ( 20 2 ¯ 1 ¯ ) planes the blue band is related only to ON – MgGa donor-acceptor pair (DAP) transitions, while for ( 20 2 ¯ 1 ) plane the incorporation of Mg-H complexes occurs additionally to the formation ON – MgGa DAP.
- Published
- 2016
39. Multicolor photon emission from organic thin films on different substrates
- Author
-
I. B. Olenych, Lidia I. Yarytska, G. Sasnouski, A. Kukhta, Anatoli I. Popov, A. Lugovskii, Andriy Luchechko, Yu. Olenych, and Ivan Karbovnyk
- Subjects
Radiation ,Materials science ,Optical glass ,Silicon ,business.industry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Porous silicon ,01 natural sciences ,0104 chemical sciences ,Organic molecules ,Organic film ,Photon emission ,chemistry ,Optoelectronics ,Thin film ,0210 nano-technology ,business ,Luminescence ,Instrumentation - Abstract
Thin films of 1-pentyl-2 / ,3 / -difluoro-3 /// -methyl-4 //// -octyl- p -quinquephenyl and 9,10-Bis (4-pentylphenylethynyl)antracene organic molecules were grown on optical glass, silicon and porous silicon substrates. First optical and luminescent properties of such hybrid composites are thoroughly studied using spectroscopic techniques. The strong decrease of aggregation in thin films of 1-pentyl-2 / ,3 / -difluoro-3 /// -methyl-4 //// -octyl- p -quinquephenyl on porous silicon was observed. The possibility of simultaneous red, green and blue tunable photon emission from organic film/porous silicon hybrid structure is demonstrated.
- Published
- 2016
40. Cathodoluminescence characterization of polystyrene-BaZrO3hybrid composites
- Author
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Ivan Karbovnyk, Volodymyr Savchyn, Yu. Yu. Horbenko, Halyna Klym, Anatoli I. Popov, Olena Aksimentyeva, A. Moskina, and Vera Serga
- Subjects
010302 applied physics ,Materials science ,Nanocomposite ,Physics and Astronomy (miscellaneous) ,General Physics and Astronomy ,Cathodoluminescence ,02 engineering and technology ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nanocrystalline material ,chemistry.chemical_compound ,Lattice constant ,chemistry ,0103 physical sciences ,Polystyrene ,Composite material ,0210 nano-technology ,Spectroscopy ,Luminescence - Abstract
The radiation properties and the electronic structure of hybrid composites based on suspension polystyrene (PS) and nanocrystals of BaZrO3 (BZO) (d < 50 nm) have been studied using luminescent spectroscopy and x-ray analysis. A strong cathodoluminescence (CL) in BZO-nanocrystals is observed in temperature range 80–293 K. It is modified in BZO-PS composites: both the low- and a high-energy bands (near 4 eV) appear, together with a significant reduction in the CL intensity. A decrease of the lattice parameter a for BZO phase in the composite and the modification of CL spectra indicate for changes in the nanocrystalline structure induced by the polymer.
- Published
- 2016
41. Impedance characterization of Cr3+, Y3+ and Zr4+ activated forsterite nanoceramics synthesized by sol–gel method
- Author
-
Halyna Klym, Ivan Bolesta, Ya. Vakhula, I. Lutsyuk, I. Borshchyshyn, and Ivan Karbovnyk
- Subjects
Diffraction ,Materials science ,Mineralogy ,02 engineering and technology ,Thermal treatment ,engineering.material ,01 natural sciences ,0103 physical sciences ,Materials Chemistry ,Ceramic ,Electrical impedance ,Sol-gel ,010302 applied physics ,Process Chemistry and Technology ,Doping ,Forsterite ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Dielectric spectroscopy ,Chemical engineering ,visual_art ,Ceramics and Composites ,engineering ,visual_art.visual_art_medium ,0210 nano-technology - Abstract
The synthesis of forsterite-based ceramic nanopowders using sol–gel method assisted by further thermal treatment has been performed. X-ray diffraction and SEM analysis of the obtained nanopowders are presented. Detailed impedance spectroscopy study of the forsterite nanoceramics doped with Cr3+, Y3+ and Zr4+ ions has been carried out. Impedance spectra are interpreted in terms of equivalent circuits. Peculiarities of the electrical properties for each of the materials under study are discussed.
- Published
- 2016
42. A Study of the Characteristics of the Fibonacci Modified Additive Generator with a Delay
- Author
-
Yuriy Kostiv, Ivan Karbovnyk, Mariia (Mandrona) Shabatura, Volodymyr Maksymovych, and Oleh Harasymchuk
- Subjects
Generator (computer programming) ,Lagged Fibonacci generator ,Fibonacci number ,Control and Systems Engineering ,Arithmetic ,Software ,Information Systems ,Mathematics - Published
- 2016
43. On the Mechanism of Nanostructure Growth on the Surface of CdI2 Crystals
- Author
-
V. M. Lesivtsiv, M. V. Partyka, N. V. Gloskovskaya, Z.M. Yaremko, Ivan Karbovnyk, I. N. Rovetskii, S. Velgosh, and Ivan Bolesta
- Subjects
дифузiя ,atomic force microscopy ,Nanostructure ,Materials science ,атомно-силова мiкроскопiя ,diffusion ,nanopores ,nanoclusters ,General Physics and Astronomy ,Crystal growth ,Iodine compounds ,нанопори ,Chemical engineering ,поверхня Ван-дер-Ваальса ,нанокластери ,van der Waals surface - Abstract
Atomic force microscopy studies of the dynamics of the nanostructure formation on a van der Waals surface of CdI2 crystals during aging in air environment under near-equilibrium thermodynamic conditions have been carried out. The nanostructure growth process is found to consist of three stages. At the first stage, there appear nano-sized pores due to the lattice dissolution at the outcrops of screw dislocations or other structural defects. At the second stage, the cone-shaped nanoclusters arise and grow in those nano-sized pores. At the third stage, the nanoclusters coagulate. The growth kinetics of cone-shaped nanoclusters is described by a diffusion model based on the interdiffusion approximation for the components. The growth rate of nanoclusters is shown to depend on the time evolution of the concentration gradient of Cd2+ ions in the near-reaction zone., Методами атомно-силової мiкроскопiї дослiджено динамiку формування нанорозмiрних структур на ван-дер-ваальсовiй поверхнi кристалiв СdI2 пiд час їхнього витримування в атмосферi повiтря за термодинамiчних умов, близьких до рiвноважних. У формуваннi поверхневих наноструктур виявлено три стадiї: на першiй утворюються нанопори через розчинення матрицi у мiсцях виходу гвинтових дислокацiй або iнших структурних дефектiв ґратки, на другiй у цих нанопорах зароджуються конусоподiбнi нанокластери, якi з часом збiльшуються у розмiрах, i на останнiй третiй стадiї вони коагулюють. Кiнетика росту поверхневих конусоподiбних нанокластерiв описана дифузiйною моделлю, яка ґрунтується на зустрiчнiй дифузiї компонентiв, що входять до їхнього складу. Показано, що швидкiсть росту цих нанокластерiв залежить вiд часової змiни градiєнта концентрацiї iонiв кадмiю у приреакцiйнiй областi.
- Published
- 2015
- Full Text
- View/download PDF
44. New Interference Technique for Determination of Low Loss Material Permittivity in the Extremely High Frequency Range
- Author
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Mykhailo Lobur, Nazariy Andrushchak, Ivan Karbovnyk, Yevhen Yashchyshyn, Konrad Godziszewski, and Anatoliy Andrushchak
- Subjects
Permittivity ,Materials science ,business.industry ,Relative permittivity ,Dielectric ,Electromagnetic radiation ,Optics ,Interference (communication) ,Extremely high frequency ,Range (statistics) ,Sapphire ,Electrical and Electronic Engineering ,business ,Instrumentation - Abstract
In this paper a new interference technique for material permittivity determination in the extremely high frequency range using a vector network analyzer is described. The novelty of this technique is the absence of a reference interference channel and there is no need to rotate the experimental sample that simplifies the measurement process and increases its accuracy. In order to approve this technique, the respective experimental setup was designed. The setup structure and theoretical background of interference fringe minimum formation were described. Based on the quasi-optical principle of the setup operation, the formula for the calculation of the material permittivity was derived. Two different dielectric materials were subjected to test measurements using the created experimental setup. Obtained average values of permittivity in the $50\div 70$ GHz range are $\varepsilon =$ 10.67 ± 0.09 and $\varepsilon =$ 2.35 ± 0.03 for sapphire and optical glass, respectively. For the purposes of result verification, the time-domain processing technique was also applied to calculate the permittivity of these materials. Besides, the obtained data are compared with those reported in the literature.
- Published
- 2015
45. Structural investigation of crystallized Ge-Ga-Se chalcogenide glasses
- Author
-
Oleh Shpotyuk, Halyna Klym, Laurent Calvez, Ivan Karbovnyk, Anatoli I. Popov, Ivan Franko National University of Lviv, Jan Dlugosz University in Czestochowa, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Latvia (LU), Ministry of Education and Science of Ukraine, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
- Subjects
Materials science ,Chalcogenide ,Functional materials ,In-process ,02 engineering and technology ,01 natural sciences ,Selenium compounds ,Annealing ,chemistry.chemical_compound ,Atomic force microscopy ,Germanium compounds ,0103 physical sciences ,Nanotechnology ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS ,010302 applied physics ,Gallium compounds ,High temperature modification ,021001 nanoscience & nanotechnology ,3. Good health ,Crystallography ,Crystallization transformations ,Structural investigation ,chemistry ,Surface crystallization ,Chalcogenide glass ,Glass ,0210 nano-technology ,Chalcogenides - Abstract
H. Klym thanks to the Ministry of Education and Science of Ukraine for support and Dr. P. Demchenko for the assistance in XRD experiments., Crystallization transformation in the 80GeSe2-20Ga2Se3 chalcogenide glasses caused by annealing at 380 °C during different duration (25, 50, 80 and 100 hours) are studied using X-ray diffraction and atomic force microscopy methods. It is established that GeGa4Se phase of low- and high-temperature modification, Ga2Se3 phase (α- and γ-modification) and GeSe2 phases are crystallized during this process. It is shown that annealing duration over 50 h does not lead to further internal structural crystallization, while annealing for 80 h result in processes of surface crystallization., Ministry of Education and Science of Ukraine; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²
- Published
- 2018
46. Морфологія та оптичні властивості наноструктур, які формуються у нестехіометричних кристалах СdI2
- Author
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N. V. Gloskovskaya, Ivan Karbovnyk, I. N. Rovetskii, Ivan Bolesta, S. V. Rykhlyuk, and S. Velgosh
- Subjects
Materials science ,Nanostructure ,Morphology (linguistics) ,atomic force microscopy ,раманівський спектр ,absorption spectra ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,спектр поглинання ,Chemical engineering ,0103 physical sciences ,nanostructures ,surface morphology ,Raman spectra ,морфологія поверхні ,010306 general physics ,0210 nano-technology ,атомно-силова мікроскопія ,Stoichiometry ,наноструктури - Abstract
The morphology of nanostructures formed in non-stoichiometric CdI2 crystals has been studied, by using the atomic force microscopy methods. Morphological changes are observed, when the concentration of cadmium atoms approaches a non-stoichiometric threshold value of 0.1 mol%. The features in the phase composition of nanostructures are analyzed with the help of Raman and infrared absorption spectroscopies. The influence of the researched nanostructures on the optical characteristics of non-stoichiometric CdI2 crystals is analyzed., Методами атомно-силової мiкроскопiї дослiджено морфологiю нанорозмiрних структур, якi формуються у нестехiометричних кристалах СdI2. Встановлено iснування граничної концентрацiї надстехiометричних атомiв кадмiю (0,1 мол.%), при якiй спостерiгається змiна морфологiї. Особливостi фазового складу сформованих наноструктур вивчалися методами комбiнацiйного розсiяння свiтла та iнфрачервоного поглинання. Проаналiзовано вплив цих наноструктур на оптичнi характеристики нестехiометричних кристалiв СdI2.
- Published
- 2018
- Full Text
- View/download PDF
47. Microstructure of Modified Cu0.4 Ni0.4 Co0.4 Mn1.8 O4 Ceramics for Temperature Sensor Electronics
- Author
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Oleh Shpotyuk, Halyna Klym, Ivan Hadzaman, and Ivan Karbovnyk
- Subjects
Materials science ,Spinel ,Analytical chemistry ,Radius ,engineering.material ,Microstructure ,Nanopore ,Specific surface area ,visual_art ,Phase (matter) ,visual_art.visual_art_medium ,engineering ,Ceramic ,Contact area - Abstract
It is shown that the micro and macro modified $Cu_{0,4}Ni_{0,4}Co_{0,4}Mn_{1,8}O_{4}$ ceramics are single-phase (contains only the main cubic spinel phase). Different modifications of ceramics are displayed in the size and shape of pores. In micro ceramics there is a more intensive growth of the contact area between the grains, increases the specific surface area. The grain is combined into agglomerates. One peak with nanopore with radius centered near ~ 2 nm is peculiar to macro ceramics. Double maximum is characteristic to micro ceramics (~ 2.3 and 5.5 nm).
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- 2018
48. Electrical Properties at Low Temperatures of PEDOT-based Nanocomposites
- Author
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Dmytro Lukashevych, Dmytro Chalyy, Ivan Karbovnyk, and Halyna Klym
- Subjects
chemistry.chemical_classification ,Nanotube ,Range (particle radiation) ,Materials science ,Nanocomposite ,Composite number ,Polymer ,Carbon nanotube ,law.invention ,Physics::Fluid Dynamics ,Condensed Matter::Materials Science ,PEDOT:PSS ,chemistry ,law ,Composite material - Abstract
Electrical properties of single- and multi-walled carbon nanotubes composites were investigated in the range of 50 to 200 K. It is established that composite films with multi-walled nanotubes loading show lower resistances as compared to their single-walled counterpart.
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- 2018
49. Computer simulation of field-controlled percolation in 3D system of straight nanotubes
- Author
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Yuri Olenych, Ivan Karbovnyk, and Halyna Klym
- Subjects
Nanotube ,Materials science ,Field (physics) ,02 engineering and technology ,Solid modeling ,Carbon nanotube ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Condensed Matter::Materials Science ,law ,Percolation ,Electric field ,Cluster (physics) ,Statistical physics ,0210 nano-technology ,Dispersion (chemistry) - Abstract
Analysis of percolation phenomenon in the system of straight nanotubes is carried out and an appropriate model of the process is proposed. An algorithm for finding the probability of nanotubes percolation is implemented using three-dimensional graphics visualization tools. The effect of geometric size and concentration of the nanotubes on the percolation probability was investigated. Based on the analysis of the dependence of percolation probability on the values of the dispersion angles determining the nanotubes orientation, the basic regularities of the conductive cluster formation under the influence of an electric field are established. The optimal parameters of the nanotube system with field-controlled percolation were determined.
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- 2018
50. Modified Positron Annihilation Lifetime Spectroscopy Method for Investigation of Nanomaterials with Advanced Porosity
- Author
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Ivan Karbovnyk, Oleh Shpotyuk, Adam Ingram, and Halyna Klym
- Subjects
Annihilation ,Materials science ,010308 nuclear & particles physics ,Nanoparticle ,02 engineering and technology ,Radius ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Nanomaterials ,Positron ,0103 physical sciences ,Physics::Chemical Physics ,0210 nano-technology ,Porosity ,Spectroscopy ,Order of magnitude - Abstract
Modified method for measuring of positron annihilation spectra on the example of humidity-sensitive MgO-Al 2 O 3 ceramics with advanced nanoporousity is proposed. It is shown that in the expansion of spectra into four components it is possible to estimate the nanopor sizes and to study the processes occurring in them. It was established that the nanoparticle fraction with a radius of ∼ 1.5 nm is an order of magnitude higher than the proportion of pores with a radius of ∼ 0.3 nm, in which also the ortho-positronium annihilation in adsorbed water occurs.
- Published
- 2018
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