Факультет електроніки та інформаційних технологій (ЕлІТ)
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Item Improvement of Mechanical, Thermal and Optical Properties of Barium Mixed Cobalt Tartrate Hydrate Crystals Grown by Gel Method(Sumy State University, 2015) Vanaja, S.; Selvamurugan, V.; Chandrasekar, P.V.; Krishna Sharma, R.; Alagar, M.In this present work, CTH and BCTH crystals have been prepared by gel technique by using single diffusion method at room temperature. The as grown crystals were characterized by using XRD, FT-IR, UV, TG / DTA and Micro hardness studies. X-ray powder diffraction results analyzed by using suitable software suggest that a CTH and BCTH crystals belong to cubic crystal system. The unit cell volume is observed to increase with increase in the concentration of barium in cobalt tartrate due to the lattice distortion. The band gap and optical properties have analyzed by UV-Visible spectrum. The functional groups and compound formation of the crystals have been studied by FT-IR spectrum. The mechanical properties of the grown crystals were tested by using Vicker’s microhardness studies. The work hardening coefficient (n) was determined to be 3.7 for CTH, 5.3 for BCTH (1 : 1) and 6.4 for BCTH (2 : 1) and the stiffness constants for different loads were calculated and reported. Thermal analysis suggests that pure cobalt tartrate starts decomposing at 73.2 C whereas the barium mixed cobalt tartrate brings about better thermal stability which increases with an increase in barium concentration.Item Structural and Optical Studies of 100 MeV Ni+7 Irradiated Cadmium Selenide Thin Films(Sumy State University, 2015) Singh, Rajesh; Yadav, A.D.; Jadhav, V.; Dubey, S.K.The effect of irradiation with Swift (100 MeV) Ni+ 7 ions on the structural and optical properties of Cadmium Selenide (CdSe) thin films have been investigated at different fluencies in the range of 1 1011- 1 1013 ions/cm – 2. The CdSe films on glass substrates were prepared by thermal evaporation. The structural and optical changes with respect to increasing fluence were observed by the means of X-ray diffraction (XRD), UV-VIS and Raman spectroscopy. After irradiating the films with Ni+ 7 ions XRD show the increased in peak intensity and crystallite size with increasing fluence. The UV-VIS-IR spectroscopy revealed that there is decrease in band gap energy of the films after irradiation with increasing fluencies. Raman spectrum for as deposited and irradiated films show two peak, one at 209 cm – 1 and at 410 cm – 1 which is assigned to the longitudinal optical (LO) phonon mode.Item Analysis of the Influence of Deposition Conditions on the Structure of the Coating Nb-Al-N(Sumy State University, 2015) Ivashchenko, V.I.; Skrynskiy, P.L.; Rogoz, V.N.; Kupchishin, A.I.; Węgierek, P.Nanocomposite Nb-Al-N films prepared by magnetron sputtering have been studied. It has been found that, in the films, there are two stable crystalline structural states, namely, NbNz and B1-Nb1 – xAlxNyO1 – y, and an amorphous like component related to aluminum oxynitride upon reactive magnetron sputtering. The substructure characteristics are sensitive to the current supplied to an Al target and related to the Knoop nanohardness and hardness, which change within in the ranges of 29-33.5 and 46-48 GPa, respectively. Ab initio calculations for the NbNz and Nb2AlN phases and NbN / AlN heterostructures have been performed to interpret the obtained results for the first time.Item Structural and Morphological Study of Nickel Doped Tin Oxide Nanoparticles Synthesized Via Sol-Gel Technique(Sumy State University, 2015) Singh, V.; Singh, D.; Kumar, S.; Maan, A.S.In the present paper nickel doped tin oxide nanoparticles were synthesized by using simple sol–gel technique. The as-synthesized sample was characterized by means of X-ray powder diffraction (XRD) spectroscopy and Energy-dispersive X-ray spectroscopy (EDX) techniques for its structural analysis. XRD spectrum reveals that all the nanoparticles are highly polycrystalline in nature and five major peaks were clearly observed. Ni-doped SnO2 crystals existed mainly as tetragonal rutile structure. The average particle size of the nanoparticles was calculated by using the Scherrer formula and it was obtained 20 nm. EDX analysis confirms the presence of Nickel. No other impurities were found. The morphology of the nanoparticles was analyzed by using scanning electron microscope (SEM). The SEM image of the studied nanoparticles confirms the existence of very small, homogeneously distributed, spherical and crystalline nanoparticles.Item Synthesis, Characterization, and Size Control of Zinc Sulfide Nanoparticles Capped by Polyethylene Glycol(Sumy State University, 2015) Allehyani, S.H.A.; Seoudi, R.; Said, D.A.; Lashin, A.R.; Abouelsayed, A.Zinc sulfide nanoparticles were synthesized with controllable size via chemical precipitation. highresolution transmission electron microscopy (HRTEM) and X-ray powder diffraction (XRD) showed that the samples were grown with the cubic phase; the particle size was varied by varying the molar ratios of zinc chloride and sodium sulfide in the presence of poly(ethylene glycol). The optical band gap was calculated on the basis of ultraviolet-visible spectroscopy (UV-VIS) and ranged from 4.13 eV to 4.31 eV depending on the particle size. Surface passivation and adsorption of poly(ethylene glycol) on the nanoparticles was explained on the basis of Fourier transform infrared measurements (FTIR).Item The Study of the Alginate / Hydroxyapatite Composites Structural Properties(Sumy State University, 2014) Суходуб, Леонід Федорович; Суходуб, Леонид Федорович; Sukhodub, Leonid Fedorovych; Kuznetsov, V.N.; Sukhodub, L.B.This paper describes the synthesis of sodium alginate (Alg) / hydroxyapatite (HA) composites and the influence of the presence of Alg on HA crystallization. Such composites become rather widespread in recent years, and are used in medicine generally for the controlled drug delivery [1‑3]. In one’s case, Alg is used as the functional and cost-effective replacement of the collagen for the creation of implants similar to the natural bone [4]. It was shown that the presence of Alg and the increase of its concentration leads to the decrease of the HA crystallinity thus providing an ability to control its levels in the resulting product. The FTIR studies confirm the incorporation of Alg in the Alg / HA composite structure.Item Effect of Substrate Temperature on the Structural Properties of CdxZn1-xTe Films Grown by Close-Spaced Sublimation Method(Sumy State University, 2014) Znamenshchykov, Y.V.; Kosyak, V.V.; Опанасюк, Анатолій Сергійович; Опанасюк, Анатолий Сергеевич; Opanasiuk, Anatolii Serhiiovych; Stanislavov, A.; Kuznetsov, V.; Gnatenko, Yu.P.In this work by energy dispersive analysis of X-rays, scanning electron microscopy and X-ray diffraction methods films of CdxZn1-xTe solid solution, obtained by a close-spaced vacuum sublimation technique under different temperatures of glass substrate, has been studied. Films were deposited by the co sublimation of Cadmium Telluride (CdTe) and Zinc Telluride (ZnTe) chunks, mixed in the ratio of 2:1. The effect of substrate temperature on the surface morphology, elemental and phase composition, lattice parameter, scattering domain sizes has been studied. The results of these studies can be used for obtaining absorber layers of tandem solar cells, basic layers of X-ray and gamma detectors.Item Structure and Properties NbN and Nb-Si-N Deposited by Magnetron Sputtering(Sumy State University, 2014) Ivashchenko, V.I.; Scrynskyy, P.L.; Lytvyn, O.S.; Rogoz, V.M.; Sobol, O.V.; Kuzmenko, A.P.NbN and Nb-Si-N films were deposited by magnetron sputtering the Nb and Si targets on silicon wafers at various bias voltage, Us. The films were investigated by an atomic force microscope (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nanoindentation. The deposited films were annealed to establish their thermal stability. The NbN films were nanostructured, and the Nb-Si-N films had a nanocomposite structure, and represented an aggregation of δ-NbNx nanocrystallites embedded into the amorphous Si3N4 tissue (nc-δ-NbNx/a-Si3N4).Item Thickness Dependent Structural, Magnetic and Transport Properties of of Cu / Co Thin Film and Multilayer Structures(Sumy State University, 2014) Brajpuriya, R.; Vyas, A.Structural, magnetic and transport properties of electron beam evaporated Co/Cu thin film and multilayer structures (MLS) having different layer thicknesses have been characterized using XRD, MOKE and resistivity techniques. The structural studies show different crystal structures for different sub-layer thicknesses. The Co (300 Ǻ) single layer film is amorphous, while Cu (300 Ǻ) film is microcrystalline in nature. The particle size is found to decrease as the number of interfaces increase. The corresponding magnetic and resistivity measurements show an increase in saturation field and resistivity. However, coercivity decreases with decrease in particle size. The results conclude that these properties are greatly influenced by various micro structural parameters such as layer thickness, number of bilayers and the quality of interfaces formed under different growth conditions.Item Synthesis and Characterization of Polyethylene Vinyl Acetate / ZnSe Nanocomposite(Sumy State University, 2013) Mathen, J.J.; Augustine, A.J.; Sebastian, J.; Madhavan, J.; Joseph, G.P.In the not too distant past, polymer scientists and technologists expanded their horizons from consum-er products to the high technology arena, particularly notable in opto - electronic applications. Ethylene Vinyl Acetates (EVA) are popular because of their superior adhesion to most substrates as well as their ease of formulation. Its High transparency is a key attribute for photovoltaic cell encapsulation. It is ex-pected that with the addition of ZnSe nano fillers, EVA becomes a high refractive index polymer (HRIP) with refractive index 2.5 and posses anti-reflective property. In this work, ZnSe nanoparticles were syn-thesised by solvo-thermal method. Nano – Composite matrices based on polyethylene vinyl acetate / ZnSe were prepared by chemical replacement mechanism. Refractive index of prepared polymer nanocomposites were calculated from dielectric study using Hioki 3532-50 LCR HITESTER at various frequencies and temperatures. The presence of nano filler enhanced the refractive index and it varied with frequency and temperature. UV-Vis-NIR Spectra of the samples enable to determine the bandgap and was found to de-crease with increasing the concentration of nano fillers dispersed in polymer matrix. I-V characteristics of the nanocomposites were plotted at various concentrations of nano fillers and at various temperatures. 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