Nano Studies

Synthesis, characterization and evaluation of antibacterial properties of Aloe vera / chondroitin sulfate / nanocellulose nanocomposite hydrogel

2023-06-24T15:22:40+04:00

Synthesis, characterization and evaluation of antibacterial properties of Aloe vera / chondroitin sulfate / nanocellulose nanocomposite hydrogel. / M. R. Mohammad Shafiee, P. Farsaiee Nejad, Z. Shams Ghahfarokhi. / Nano Studies. – 2021–2022. – # 21/22. – pp. 63-74. – eng. The synthesis of nanocomposite hydrogel as an antibacterial agent is reported. The nanocomposite hydrogel was synthesized using freeze-drying method by blending Aloe vera, chondroitin sulfate and nanocellulose. The synthesized nanocomposite was characterized using Fourier transform infrared (FT–IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The evidence showed that there is a noteworthy chemical interaction between the Aloe vera, chondroitin sulfate and nanocellulose. In addition, equilibrium degree of swelling of nanocomposite hydrogel was determined gravimetrically. The antibacterial studies of Aloe vera / chondroitin sulfate / nanocellulose nanocomposite hydrogel was evaluated against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) bacteria. The results illustrated that the nanocomposite hydrogel has good antibacterial activity against gram-positive and gram-negative bacteria and can be suitable for antimicrobial applications. Fig. 7, Ref. 39.

137Cs radionuclide migration in soil of Georgian resorts after 31 years from Chernobyl accident

2023-08-13T22:49:02+04:00

¹³⁷Cs radionuclide migration in soil of Georgian resorts after 31 years from Chernobyl accident. / N. Kuchava, P. Imnadze, I. Nikolaishvili, L. Chkhartishvili. / Nano Studies. – 2021–2022. – # 21/22. – pp. 75-82. – geo. There is studied the vertical migration of ¹³⁷Cs radionuclide in the soil of two Georgian resorts – Ureki and Bakhmaro – located at different height from the Black Sea level after 31 years from the Chernobyl accident. The samples were gathered in 2017, i.e., after a period of it’s half-decay. The great interest to the ¹³⁷Cs migration problem is caused by its physical-chemical properties. The samples of soil in both places were taken on one and the same day (July 15) in the different depths of soil: 0 (surface), 10, 20, 30 and 40 cm. For the investigated two different types of soil the different characters of vertical migration of ¹³⁷Cs radionuclide is clearly seen. Fig. 1, Tab. 1, Ref. 16.

Iron–nickel alloy additive effect on composite materials obtaining and properties

2023-08-13T22:52:11+04:00

Iron–nickel alloy additive effect on composite materials obtaining and properties. / L. Rurua. / Nano Studies. – 2021–2022. – # 21/22. – pp. 83-90. – geo. The study aims to determine the iron–nickel FeNi alloy additive effect on the Ti–Al–Mg–Si–B–C system, in particular, TiB₂–TiC–SiC based unalloyed and AlMgB₁₄ compound alloyed, composite materials. The samples, both with and without the addition of FeNi alloy to these composites, were prepared by the spark-plasma synthesis method. Their structure and properties were compared. When FeNi alloy is added, the composite can be sintered at a lower temperature, which reduces electricity costs. At the same time, the porosity of the composite is also reduced, since the grains of FeNi are placed between the grains of the composite basis and thus fill the existing pores. Fig. 6, Tab. 3.

Preparation of graphene oxide composites containing nanometals and oxides from graphite foil wastes and study of their biocidal activity

2023-06-26T13:48:20+04:00

Preparation of graphene oxide composites containing nanometals and oxides from graphite foil wastes and study of their biocidal activity. / T. Dundua. / Nano Studies. – 2021–2022. – # 21/22. – pp. 91-110. – eng. Graphene oxide (GO) is obtained using improved Hummers method by oxidation of powdered graphite foil wastes (pGFW) at low (~ 0 °C) and relatively high (~ 50 °C) temperatures. GO–Me(NO₃)_x complexes are synthesized by the interaction of GO and metal nitrates; further heat treatment in vacuum (exfoliation) leads to the production of composites containing reduced graphene oxide (rGO), nano-sized metals (Cu and Ag), and oxide (Fe₂O₃). The rGO–TiO₂ (nano)composite was obtained by hydrolysis of titanium alkoxide and subsequent heat treatment in the presence of GO. Composites have been shown to have high antibacterial activity both against gram-positive and negative bacteria. Fig. 14, Ref. 52.

Gold nanoparticles mediated tuning of thermo-optical parameters in gold nanoparticles doped cholesteric liquid crystal nanocomposite

2023-08-13T22:58:37+04:00

Gold nanoparticles mediated tuning of thermo-optical parameters in gold nanoparticles doped cholesteric liquid crystal nanocomposite. / G. Petriashvili, L. Devadze, Ts. Zurabishvili, N. Sepashvili, A. Chirakadze, T. Bukia, J. Markhulia, M. Areshidze, L. Sharashidze, Sh. Akhobadze, E. Arveladze, G. Sanikidze. – 2021–2022. – # 21/22. – pp. 111-124. – eng. Systems of nanoparticles (NPs) dispersed in liquid crystals (LCs) have attracted attention for the possible development of novel materials based on the controlled assembly of the NPs. There is investigated the formation of free-standing nanocomposites formed by the co-assembly of gold nanoparticles (GNPs) in the cholesteric liquid crystal (CLC) structures. It is found that increasing the concentration of GNPs in the CLC-mixture causes a significant modification of CLC structure and tuning of selective reflection band (SRB) over the optical spectrum. Furthermore, it is demonstrated that a light emission in the luminescent dye-doped CLC/GNPs-nanostructure can be increased dramatically when doped with a certain quantity of GNPs. The pumping laser beam onto the CLC/GNPs-nanostructure causes a temperature increase of this nanocomposite followed by SRB shifting of and spectral tuning of the stimulated laser emission lines from CLC/GNPs-nanocomposite. Fig. 11, Ref. 24.

Technology of terbium monotelluride nanofilms and their electrophysical and mechanical properties

2023-08-13T23:02:21+04:00

Technology of terbium monotelluride nanofilms and their electrophysical and mechanical properties. / Z. U. Jabua, A. V. Gigineishvili. / Nano Studies. – 2021–2022. – # 21/22. – pp. 125-128. – eng. Rare earth chalcogenides possess interesting electrophysical, magnetic, optical, thermal, mechanical, etc. properties. Work aims to develop the terbium monotelluride TbTe nanofilms deposition technology on various substrates and study some of their electrophysical and mechanical properties. 0.2 – 0.8 µm thick films are prepared by vacuum-thermal evaporation from two independent sources of Tb and Te. Deposition temperatures of terbium and tellurium evaporators are ~1600 and ~780 K, respectively. And distances from Tb and Te evaporators to a substrate are 23 and 49 mm, respectively. Deposition rate is of 55 Å/s. Substrate temperature changes within the range of 720 – 1150 K. Fused silica (sitall), sapphire and (111) oriented single-crystalline silicon plates are used for substrates. Substrate optimal temperature is shown to be in the range 980 – 1100 K. According to the X-ray diffraction and microanalysis, any of obtained films has the NaCl-type structure with lattice constant of 6.10 Å and contain Tb and Te, respectively, around 50.1 and 49.9 at.%. With the increase in the substrate temperature from 980 to 1100 K the film grain size increases from 23 to 49 nm. With an increase in particle size, the resistivity decreases from 4.0∙10^–6 to 3.2∙10^–6 Ohm∙m. All investigated films have n-type conductivity. The relative mechanical strength is investigated by the complete abrasion method on films with same thickness (of ~0.7 μm), load (of 180 g) and deposition temperature, but prepared on different substrates. Relative strength decreases in the sequence: sapphire–sitall–silicon, which is consistent with the data that the greater difference between tthermal expansion coefficients of film and substrate materials, the less relative strength of the film. Fig. 6, Ref. 6.

Investigation of durability of geopolymer materials obtained using thermally modified clay rocks

2023-08-13T23:07:27+04:00

Investigation of durability of geopolymer materials obtained using thermally modified clay rocks. / E. Shapakidze, M. Avaliani, M. Nadirashvili, V. Maisuradze, I. Gejadze, T. Petriashvili, E. Khuchua. – 2021–2022. – # 21/22. – pp. 129-136. – eng. World cement industry currently accounts for about 8% of the global carbon dioxide emissions from clinker production by firing the carbonate component of the raw mix. Geopolymer materials can be an alternative to ordinary Portland cement, as carbon dioxide emissions are reduced by about 80%. In addition, given that geopolymer concretes are generally stronger and more durable, they offer a longer service life, which reduces the need for raw materials in the future. Metakaolin, a product of heat treatment of kaolin clays at temperatures of 750 – 850°C, is usually used to obtain geopolymer materials, but limited world reserves of kaolin clays prevent their widespread use. Paper describes the production of geopolymer materials synthesized on the basis of thermally modified clay rocks and their study for durability. Studies have shown that geopolymer materials have good durability and higher resistance to aggressive solutions compared to ordinary Portland cement. Fig. 4, Tab. 3, Ref. 28.

Substrate temperature effect on Yb5Sb4 films mechanical strength

2023-08-13T23:11:24+04:00

Substrate temperature effect on Yb₅Sb₄ films mechanical strength. / Z. Jabua, V. Marchilashvili, A. Gigineishvili. – 2021–2022. – # 21/22. – pp. 137-140. – rus. By the method of discrete vacuum-thermal evaporation, the crystalline 1.2 μm thick films of composition Yb₅Sb₄ are prepared on a leucosapphire substrate. It has been shown that single-phase crystalline films are formed in the substrate temperature region of 1010 – 1280 K. It is studied the substrate temperature effect on the mechanical strength of films prepared in this way. It is shown that with an increase in the substrate temperature in the region of 1010 – 1200 K the mechanical strength increases linearly almost three times, while in the region of 1200 – 1280 K it saturates and then remains constant. It has been suggested that the increase in strength is associated with both the film improved adhesion with substrate and perfection of its crystalline structure. Fig. 2, Ref. 5.

Morphological changes in vapor grown Zn and ZnO nano- and microstructures

2023-08-13T23:15:04+04:00

Morphological changes in vapor grown Zn and ZnO nano- and microstructures. / A. Jishiashvili, Z. Shiolashvili, N. Makhatadze, A. Chirakadze, V. Gobronidze, T. Gagnidze, D. Jishiashvili. – 2021–2022. – # 21/22. – pp. 141-146. – eng. Zn-based crystalline nano- and micromaterials were synthesized by the pyrolytic technology at 410°C. The powders of ammonium chloride, ZnO and Zn served as source materials. At first, while the Si substrate temperature was rising up to 410°C, the ZnO microcrystals were produced by the interaction of ZnCl₂ vapor with water molecules. After the consumption of ammonium chloride and the formation of an oxygen deficient environment, the metallic Zn was providing the Zn vapor to the substrate. The hexagonal ZnO microcrystals with prismatic habit were produced, together with hexagonal crystalline Zn platelets. Finally, when the metallic Zn in the source was also completely consumed, the hollow ZnO microspheres were formed. Fig. 3, Ref. 14.

Nanocomposite hydrogels and their application for environmental remediation: In review

2023-08-13T23:18:00+04:00

Nanocomposite hydrogels and their application for environmental remediation: In review. / H. Kurama. – 2021–2022. – # 21/22. – pp. 147-162. – eng. Over the last years, nanotechnology has been implemented in almost all branches of human live. Until now, numerous nanomaterials have produced and used to eliminate inorganic and organic species from wastewater effluents, in many cases, these are found more efficient than the conventional adsorbents. Within these attempts, hydrogels as a group of polymeric materials have received high interest in recent years. The hydrophilic structure of which renders them capable of holding large amounts of water in their three-dimensional networks. The extensive employment of these products in a number of industrial and environmental areas has considered being of prime importance. In this paper, the fundamental concepts, classification, physical and chemical characteristics, production methods and technical feasibility of their utilization is reviewed based on the composite hydrogel. A special attention has given to utilization of them for wastewater purification especially for the effluent received from textile industry. Fig. 7, Ref. 52.

Development of promising cathode materials based on modified spinels for Li-ion accumulators

2023-09-02T15:11:37+04:00

Development of promising cathode materials based on modified spinels for Li-ion accumulators. / E. I. Kachibaia, T. V. Paikidze, R. A. Imnadze, Sh. S. Japaridze. – 2021–2022. – # 21/22. – pp. 163-166. – eng. Promising cathode materials based on iron-modified LiMe_xNi_0.5_–_xMn_1.5O₄ (where Me = Fe and x = 0.1 – 0.4) type compounds have been developed. Conditions for phase pure nanostructured samples with cubic spinel structure obtaining based on LiCO₃, Mn₂O₃ and Ni₂O₃ initial reagents are optimized. For this purpose, a number of solid-state synthesis methods in the 180 – 700 °C interval are used. Cathode materials based on Fe–Mn are economically attractive due to the high abundance of Mn and Fe in nature. Cathode materials for lithium–ion batteries containing iron, nickel and manganese can be a promising alternative to commercial LiCoO₂ and LiNiO₂ samples. Tab. 1, Ref. 2.

Structure, morphology and thermal behavior of silver-doped nanoparticles formed in La2(SO4)3 and LaCl3 systems

2023-09-02T15:14:18+04:00

Structure, morphology and thermal behavior of silver-doped nanoparticles formed in La₂(SO₄)₃ and LaCl₃ systems. / O. Lavrynenko. – 2021–2022. – # 21/22. – pp. 167-176. – eng. The formation of structures in systems of lanthanum sulphate and chloride in the presence of silver nitrate was studied by XRD, TG–DTA and SEM/EDS methods. TG–DTA analysis showed the formation of hexagonal structure La(OH)₃ and its transformation into an unstable compound of monoclinic lanthanum (oxy)hydroxide in the temperature range 260 – 300°C, dehydroxilation of (oxy)hydroxide’s lattice at temperatures of 420 – 440°C. The subsequent ordering of the lanthanum oxide structure and the destruction of the substances included in the system took place at temperatures of 600 – 830°C and the removing of silver clusters – at 920°C. It is shown that at Т = 400 – 600°С the well-crystallized powders formation of lanthanum oxide La₂O₃ (space group P3m1 corresponds to a trigonal system) takes place, which includes elements of cubic phases La₂O₃ (space group Ia3) and LaO (space group F) in its structure. The presence of silver cations in the systems during the calcination process leads to their reduction on the surface of lanthanum oxide clusters. Morphological study indicates the heterogeneity of the powders and the distortion of the (hexagonal) shape of lanthanum oxide crystals to spherical that is typical for lanthanum chloride systems. In addition to the main elements (oxygen, lanthanum and silver if present in the system) the composition of the powders contains the elements that make up the anions of the initial salts (sulphur, chlorine, nitrogen), as well as the residual elements (sodium and potassium) of additional substances. Tab. 1, Fig. 3, Ref. 16.

Raman studies on carbon-containing phases in nanosized-ZrO2/C and nanosized-(ZrC,ZrO2)/C composites

2023-07-09T22:26:21+04:00

Raman studies on carbon-containing phases in nanosized-ZrO₂/C and nanosized-(ZrC,ZrO₂)/C composites. / A. Martiz, A. Farkas, Z. Karoly, F. P. Franguelli, S. K. Samaniego, A. Menyhard, L. Kotai. / Nano Studies. – 2021–2022. – # 21/22. – pp. 177-186. – eng. Raman spectroscopic studies were performed to identify the nature of the carbon-containing phases in nano-(ZrC,ZrO₂)/C composites. The nano-ZrO₂/C composites were prepared in a tube furnace by heat-treatment of zirconium-loaded sulfonated styrene-divinylbenzene resins between 1000 and 1400 °C. The plasma processing of a nano-ZrO₂/C sample in inert or reducing atmosphere resulted in nano-(ZrC,ZrO₂)/C composites. The Raman spectra of the nano-ZrO₂/C samples show that the ratio of the amorphous carbon / graphitic components decreases, whereas the fraction of distorted graphite structures increases with increasing reaction temperature and time. This can be attributed to the formation of new graphene edges by the condensation of the polyene content in the amorphous carbon. The ratio of the amorphous carbon practically does not change if the plasma treatment was performed under inert (Ar+He) atmosphere. In contrast, under reducing (Ar+H₂) atmosphere, the amorphous carbon almost completely crystallizes into graphite. The ratio of the defective / regular graphite structures and the change of the thickness or separation of the graphene (monolayer carbon) sheets are higher under inert than reducing plasma conditions. We found no catalytic effect of ZrC on the graphite crystallization under inert plasma conditions, but in the presence of H₂, ZrC may catalyze the graphitization process. Fig. 3, Tab. 4, Ref. 40.

Ruby, sapphire, diamond: Breakthrough in scientific cognition – From precious minerals to lasers, graphene, nanonanomaterials …

2023-09-02T15:16:39+04:00

Ruby, sapphire, diamond: Breakthrough in scientific cognition – From precious minerals to lasers, graphene, nanonanomaterials … . / M. Avaliani. / Nano Studies. – 2021–2022. – # 21/22. – pp. 187-222. – geo. Review paper, dedicated to the memory of author’s father – Apollon Avaliani, is focused on the following themes and is discussed in the ensuing order: Introduction; Etymology of mineral names based on their shape, composition, geographical location or properties; Historical overview, myths and symbolism; Crystal structure of colored corundums and diamond; Properties of minerals; Methods of synthesized artificial crystals and their properties; Use of corundum group crystals and diamond, consumption and utilization of carbon and its modern allotropes; and Carbon as an example of allotropic diversity, diamond, graphite, graphene and other futuristic materials. Fig. 22, Ref. 51.

Dosimetric monitoring of medical personnel radiation safety: Radiation and Nuclear Medicine Center in Tbilisi

2023-09-02T15:18:24+04:00

Dosimetric monitoring of medical personnel radiation safety: Radiation and Nuclear Medicine Center in Tbilisi. / G. Shanidze. / Nano Studies. – 2021–2022. – # 21/22. – pp. 223-266. – geo. A direct result of the recent rapid development in medical technologies is the increasing use of radiation in medicine for both diagnostic and therapeutic purposes. Accordingly, the risks of exposure not only to patients, but also to medical personnel themselves increase. The development of measures to reduce and prevent the noted risks should be based on an assessment of the state of radiation safety of medical personnel with the help of its detailed and credible monitoring. This paper, which is a Master Thesis publication, aims to study dosimetric monitoring of the radiation safety of medical personnel in the case of one specific medical institution, the Center for Radiation and Nuclear Medicine – CRNM (Tbilisi, Georgia). The introduction characterizes the problem of radiation safety of medical personnel in general. The literature review is devoted to the radiation safety monitoring in medical institutions. Then an outline of procedures for radiation diagnostics and radiation therapy in clinics, including CRNM, are carried out. There are described the dosimetric tools for monitoring the radiation safety and the dosimeters and isotope sources of radiation used at CRNM, as well as presented and analyzed the results of monitoring the radiation safety of the CRNM personnel in 2016 – 2020. Main results of the work are summarized in the form of conclusions. The minimum, average and maximum annual radiation doses received by the staff of the Center for Radiation and Nuclear Medicine were found to be 0.056, 2.076 and 7.600 mSv, respectively. One can say that this monitoring gives values of the same order as other monitorings carried out all over the world. Although, the results of this Center are somewhat overestimated. Fig. 5, Tab. 7, Ref. 23.

Technological method of increasing photosensitivity in photochromic liquid crystal polymer films

2023-09-02T15:21:56+04:00

Technological method of increasing photosensitivity in photochromic liquid crystal polymer films. / L. Devadze, G. Petriashvili, A. Chanishvili, Ts. Zurabishvili, N. Sepashvili, K. Chubinidze, Sh. Akhobadze, N. Ponjavidze. – 2021–2022. – # 21/22. – pp. 267-276. – eng. Qualitatively new polymer films consisting of photochromic spiropyran doped in the liquid crystal nemato-chiral matrix has been obtained using the technological process of the microencapsulation method improved by the authors. Studies have shown that by controlling the microencapsulation process, technological characteristics of polymer films affect their photosensitivity. Reducing the microcapsules size, increasing the films thickness and their stretching result in the increased photosensitivity. The technological method of microencapsulation is proposed by the authors as one of the directions to increase the photosensitivity of photochromic liquid crystal polymer films. Fig. 10, Ref. 15.

Mathematical model of technological process of manufacturing thin films taking into account their anisotropy and heterogeneity

2023-09-02T15:23:34+04:00

Mathematical model of technological process of manufacturing thin films taking into account their anisotropy and heterogeneity. / V. Gogichaishvili. – 2021–2022. – # 21/22. – pp. 277-286. – eng. The problem of diffusion in the fabrication process of thin-film structures with crystal anisotropy and heterogeneity is considered. Two boundary value problems A and B are posed with respect to impurity atoms in the crystal bulk. Boundary value problem A describes the process of diffusion with an open window for atoms in the gas phase (to penetrate through it into the crystal), and boundary value problem B is a diffusion process with a closed window (diffusant atoms are redistributed in the crystal during high-temperature oxidation). These boundary value problems are solved by the Green’s function method. Using the methods of tensor analysis and Riemannian geometry, the modified Green’s functions for boundary value problems A and B are determined in the form of finite analytic functions. Solutions are found as finite integral expressions, with the help of which the diffusant concentrations are calculated at an arbitrary point for various moments of time. The cases of thick (when the crystal thickness exceeds the diffusion length) and thin (when it is less than the diffusion length) crystals are considered. The Green’s function for thin crystals is plotted as infinite coinciding lines. Fig. 1, Ref. 4.

Magnetic properties of nanopowder h-BN doped with Fe and Fe3O4 nanoclusters

2023-07-09T22:33:48+04:00

Magnetic properties of nanopowder h-BN doped with Fe and Fe₃O₄ nanoclusters. / Sh. Makatsaria, Sh. Kekutia, J. Markhulia, V. Mikelashvili, L. Chkhartishvili, R. Chedia. / Nano Studies. – 2021–2022. – # 21/22. – pp. 287-292. – eng. Hexagonal boron nitride h-BN nanopowders doped with magnetic nanoclusters – ferromagnetic iron Fe and / or ferrimagnetic magnetite Fe₃O₄ – obtained by several novel chemical synthesis routes reveal the magnetic properties making useful application of these nanocomposites in BNCT (Boron Neutron Capture Therapy) for external magnetic field controlled delivery of neutron-capturing boron ¹⁰B isotopes in target tumor cells. Fig. 2, Ref. 7.

Nanosorbents in purification of wastewater and remediation of contaminated soil: A review

2023-07-09T22:38:29+04:00

Nanosorbents in purification of wastewater and remediation of contaminated soil: A review. / Ch. Ch. Aguomba, R. U. Duru, Ch. Obi, I. P. Okoye. / Nano Studies. – 2021–2022. – # 21/22. – pp. 293-308. – eng. Nanoparticles have become increasingly relevant in science and industry. This is understandable due to its varied applications from sports to medicine to cosmetics and even the military. This review focuses on the removal of heavy metal ions from contaminated soil and wastewater using nanosorbents. Well-established physical and chemical methods were examined but the focus was on green synthesis. Contaminated soil remediation and wastewater purification using nanosorbents follow the bottom up synthetic approach. Green synthesis is more advantageous than chemical approaches due to its cheapness and being environmentally friendly. Green synthesis also avoids hazardous and toxic methods of nanoparticle synthesis. It also provides a use for otherwise harmful and invasive plant materials. The importance of nanoparticles to biofuels, cosmetics and drugs and medicine was also evaluated. Challenges to more adoption of nanoparticles were also highlighted. Fig. 13, Tab. 1, Ref. 42.

In memoriam: Prof. Giorgi Tavadze (1945, January 1st – 2021, January 7th)

2023-09-02T15:29:37+04:00

In memoriam: Prof. Giorgi Tavadze (1945, January 1st – 2021, January 7th). / L. Chkhartishvili. – 2021–2022. – # 21/22. – pp. 333-344. – eng. This is a publication of the author’s presentation at the 21st International Symposium on Boron, Borides and related Materials, 2022 September 5 – 9, Paris, France (ISBB 2022) made to tribute to Prof. Giorgi Tavadze in response to the kind invitation of Dr. Nathalie Vast, the ISBB 2022 Chair. Fig. 22.

Professor Alex B. Gerasimov (1936 – 2019): Long and great life in science

2023-06-24T15:00:02+04:00

Professor Alex B. Gerasimov (1936 – 2019): Long and great life in science. / G. I. Japaridze, L. S. Chkhartishvili. / Nano Studies. – 2021–2022. – # 21/22. – pp. 7-22. – eng. The main milestones of the biography of Professor Alex B. Gerasimov, outstanding scientist, organizer of high-tech industry and educator of generations of researchers, is discussed. Fig. 55.

Obtaining thin film semiconductor oxides by stimulated plasma anodizing technology and their studying

2023-06-24T15:07:14+04:00

Obtaining thin film semiconductor oxides by stimulated plasma anodizing technology and their studying. / A. Bibilashvili, N. Dolidze, Z. Jibuti. / Nano Studies. – 2021–2022. – # 21/22. – pp. 23-38. – geo. The work is devoted to development of the technology of obtaining thin oxide films by stimulated plasma anodization and investigation of their physical properties by Professor Alex Gerasimov and his colleagues. Low-temperature methods of obtaining oxide films of metals and semiconductors, which use solid catalysts (rare earth metals) and ultraviolet light, are discussed. Electrophysical, optical and dielectric properties of obtained oxides are studied. The physical mechanism of the plasma anodization process stimulated by the action of solid catalyst and ultraviolet light in the plasma anodization process is proposed. It is shown that the following special properties of the catalyst are decisive for the solid-state catalytic plasma anodization process: presence of low-energy empty electronic orbitals and low electronegativity compared to the material to be oxidized. When stimulated by ultraviolet light, additional electrons are transferred from a bonding energy band to an antibonding one, which weakens the chemical bonds in the material to be oxidized and facilitates its atoms movement. The optimal technological modes of the stimulated plasma anodization process are determined. The possibility of using oxide films obtained by such technology to create elements of integrated circuits is discussed. Fig. 13, Tab. 1, Ref. 15.

Study and application of radiation defects in semiconductors and structures

2023-06-24T15:12:39+04:00

Study and application of radiation defects in semiconductors and structures. / N. Dolidze, A. Bibilashvili, Z. Jibuti. / Nano Studies. – 2021–2022. – # 21/22. – pp. 39-56. – geo. The article deals with the investigation of radiation defects in Ge irradiated by accelerated electrons and γ-quanta at 77 K by Prof. A. Gerasimov and his research group. Since the use of such a powerful method as electron paramagnetic resonance for determining the microstructure of solids is impossible in Ge, the data on the defects are obtained on the basis of indirect measurements such as the study of electrophysical, photoelectric, optical and mechanical properties. The nature and composition of radiation defects corresponding to the stages of annealing observed in the studies are determined. Examples of the practical use of radiation as a technological method are given. Studies of the effect of radiation on metal–dielectric–semiconductor systems are carried out. A model of radiation-induced charge accumulation in metal–insulator–semiconductor structures with Al₂O₃ for dielectric is presented. Fig. 11, Tab. 1, Ref. 42.

Mechanisms of diffusion processes in semiconductors

2023-06-24T15:16:42+04:00

Mechanisms of diffusion processes in semiconductors. / Z. Jibuti, A. Bibilashvili, N. Dolidze. / Nano Studies. – 2021–2022. – # 21/22. – pp. 57-62. – geo. The paper presents an original approach to describing the impurities diffusion processes in semiconductors developed by Professor Alex Gerasimov and his research team. The dependence of the diffusion coefficients of various impurities in Ge, Si, A^IIIB^V, A^IIB^VI and A^IVB^IV semiconducting materials on number of diffusion process conditions, in particular, temperature is studied. An analysis is done how well the standard physical models can explain the observed features of the temperature-dependences of the impurities diffusion coefficients in semiconductors. It is theoretically shown that the impurity diffusion coefficient depends on the degree of the impurity-levels population in given semiconductor at diffusion temperature. In other words, the impurities diffusion rate in semiconductors is determined by the active chemical bonds arising between the impurity and matrix atoms at that temperature. Ref. 27.

GTU nano 2021: Short chronicle and photo and screenshot gallery. 6th International Conference “Nanotechnology” in memory of Professor Alex Gerasimov – initiator of GTU’s nanoconferences

2023-09-02T15:25:43+04:00

GTU nano 2021: Short chronicle and photo and screenshot gallery. 6th International Conference “Nanotechnology” in memory of Professor Alex Gerasimov – initiator of GTU’s nanoconferences. / M. Avaliani. Nano Studies. – 2021–2022. – # 21/22. – pp. 309-322. – eng. Chronicle of the 6th International Conference “Nanotechnology” in memory of Prof. Alex Gerasimov – initiator of GTU’s nanoconferences, 2021 October 4 – 7, Tbilisi, Georgia (GTU nano 2021) is given. Fig. 24.

Some of 2021 nanoforums: ANM, ICANM, IMS, GTU nano, and HMT

2023-09-02T15:27:21+04:00

Some of 2021 nanoforums: ANM, ICANM, IMS, GTU nano, and HMT. / L. Chkhartishvili. – 2021–2022. – # 21/22. – pp. 309-322. – geo. There are given chronicles for five 2021 nanoforums: 17th International Conference on Advanced Nanomaterials, 2021 July 22 – 24, Aveiro, Portugal (ANM 2021); 8th International Conference and Exhibition on Advanced and Nanomaterials, 2021 August 9 – 11, Ottawa, Canada (ICANM 2021); 4th International Conference “Modern Technologies and Methods of Inorganic Materials Science”, 2021 September 20 – 21, Tbilisi, Georgia (IMS 2021); 6th International Conference “Nanotechnology” 2021 October 4 – 7, Tbilisi, Georgia (GTU nano 2021); and 7th International Materials Science Conference High Mat Tech, 2021 October 5 – 7, Kyiv, Ukraine (HMT 2021). Fig. 29.