Model of Formation of Nano-Sized Whiskers Out of Channels of the Triple Junctions of Grain Boundaries of Polycrystal

A model of formation of nano-sized whiskers out of channel of triple junction grain boundaries on the surface of polycrystal has developed. The model is based on the idea of the formation of the stress concentrators in the junction channels under diffusion creep of polycrystals. Model explains the increase of the growth rate whiskers under inhomogeneous distributions of internal mechanical stresses in polycrystals. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3599

Model of Formation of Nano-Sized Whiskers Out of Channels of the Triple Junctions of Grain Boundaries of Polycrystal

A model of formation of nano-sized whiskers out of channel of triple junction grain boundaries on the surface of polycrystal has developed. The model is based on the idea of the formation of the stress concentrators in the junction channels under diffusion creep of polycrystals. Model explains the increase of the growth rate whiskers under inhomogeneous distributions of internal mechanical stresses in polycrystals. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3599

Synthesis, Structure and Magnetic Properties of Copper(II) Complexes of Diphenyl-(1-propylbenzimidazol-2-yl)methanol

Two types of binuclear copper complexes [LCuN3]2 and [LCuNO3]2.of bidentate ligand - diphenyl-(1-propylbenzimidazol-2-yl)methanol (HL) in the 4:1 ratio were synthesized. The crystal structure of copper complexes shows a centrosymmetric dimeric binuclear complex with two Cu2+ cations bridged by two oxygen atoms from two organic ligands. In the complexes, a very strong antiferromagnetic exchange interaction between copper atoms is observed. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei

High-throughput small-molecule crystallography at the ‘Belok’ beamline of the Kurchatov synchrotron radiation source: Transition metal complexes with azomethine ligands as a case study

This paper concisely describes capabilities of the ‘Belok’ beamline at the Kurchatov synchrotron radiation source, related to high-throughput small-molecule X-ray crystallography. As case examples, a series of four novel transition metal complexes with azomethine ligands were selected. The complexes demonstrate somewhat unexpected changes in the coordination geometry and nuclearity in response to the introduction of substituents in the ligand’s periphery. © 2017 by the authors

Oксидування поверхні n-GaAs: морфологічний та кінетичний аналіз

Ми досліджуємо процеси направленого оксидування поверхні n-GaAs, які відбуваються в результаті електрохімічної обробки напівпровідника в водно-спиртовому розчині соляної кислоти. Аналіз вольт-амперних характеристик проведено з метою дослідження кінетики процесу, це дало змогу встановити етапи утворення оксидної плівки та острівців. Морфологія поверхні оцінена за характеристиками площі, лінійних розмірів, цільності (Solidity) та округлості (Round) острівців. Показано, що оксидування відбувається за механізмом Странського-Крастанова. Дослідження формування власних оксидів на поверхні GaAs є вкрай важливим, адже, оксиди можуть істотно впливати на властивості матеріалу. Власні оксиди напівпровідників є пасивуючою плівкою, яка надійно захищає поверхню від дії навколишнього середовища та при взаємодії з агресивними речовинами. Крім того, власні оксиди GaAs проявляють напівпровідникові властивості, що дозволяє створювати гетероструктури оксид/ GaAs з гетеропереходами для оптоелектронних застосувань.We study the directed oxidation processes of the n-GaAs surface as a result of the electrochemical treatment of a semiconductor in an aqueous-alcoholic solution of hydrochloric acid. The analysis of the voltampere characteristics was carried out in order to study the process kinetics, this made it possible to establish the formation stages of the oxide film and islands. The surface morphology was estimated according to the area characteristics, linear sizes, Solidity and Round islands. It was shown that the oxidation occurs by the Stranski-Krastanov mechanism. The formation study of own oxides on the GaAs surface is extremely important, because oxides can significantly impact the material properties. The native oxides of semiconductors are an inactive film that reliably protects the surface from environmental action and when interacting with aggressive substances. In addition, the native oxides of GaAs exhibit semiconductor properties that allow to create oxide/GaAs heterostructures with heterojunctions for optoelectronic applications

Functional model for the synthesis of nanostructures of the given quality level

Purpose: The aim of this paper is to develop a functional model for the synthesis of nanostructures of the given quality level, which will allow to effectively control the process of nanopatterning on the surface of semiconductors with tunable properties. Design/methodology/approach: The paper uses the IDEF0 methodology, which focuses on the functional design of the system under study and describes all the necessary processes with an accuracy sufficient for an unambiguous modelling of the system's activity. Based on this methodology, we have developed a functional model for the synthesis of nanostructures of the given quality level and tested its effectiveness through practice. Findings: The paper introduces a functional model for the synthesis of nanostructures on the surface of the given quality level semiconductors and identifies the main factors affecting the quality of nanostructures as well as the mechanisms for controlling the formation of porous layers with tunable properties. Using the example of etching single-crystal indium phosphide electrochemically in a hydrochloric acid solution, we demonstrate that the application of the suggested model provides a means of forming nanostructures with tunable properties, assessing the quality level of the nanostructures obtained and bringing the parameters in line with the reference indicators at a qualitatively new level. Research limitations/implications: Functional modelling using the IDEF0 methodology is widely used when process control is required. In this study it has been applied to control the synthesis of nanostructures of the given quality level on the surface of semiconductors. However, these studies require continuation, namely, the establishment of correlations between the technological and resource factors of synthesis and the acquired properties of nanostructures. Practical implications: This study has a significant practical effect. Firstly, it shows that functional modelling can reduce the time required to form large batches of the given quality level nanostructures. This has made it possible to substantiate the choice of the initial semiconductor parameters and nanostructure synthesis modes in industrial production from the theoretical and empirical perspective. Secondly, the presented methodology can be applied to control the synthesis of other nanostructures with desired properties and to reduce the expenses required when resources are depleted and the cost of raw materials is high. Originality/value: This paper is the first to apply the IDEF0 methodology to control the given quality nanostructure synthesis. This paper will be of value to engineers who are engaged in the synthesis of nanostructures, to researchers and scientists as well as to students studying nanotechnology

Synthesis, crystal structure and magnetic properties of copper(II) complexes with 4-methyl-N-[2-[(E)-2-pyridyl[alkyl]iminomethyl]phenyl]benzenesulfamide ligands

Two types of copper(II) complexes CuL1Cl and CuL2COOCH3 with tetradentate 4-methyl-N-[2-[(E)-2-pyridylmethyliminomethyl]phenyl]benzene-sulfamide (L1) and 4-methyl-N-[2-[(E)-2-pyridylethyliminomethyl]phenyl]-benzenesulfamide (L2) ligands were synthesized. The complexes were characterized by elemental analysis, infrared and 1H NMR spectra, magnetochemical measurements, and single crystal X-ray diffraction. The Cu atoms in the complexes CuL1Cl and CuL2COOCH3 are coordinated by tosylamine N,O, imino N and pyridine N atoms of the Schiff base ligand, and one Cl or acetate ligand at the apex, thus forming the strongly distorted square-pyramidal or octahedral environment, respectively. Complexes CuL1Cl and CuL2COOCH3 are paramagnetic. © 2019 Elsevier B.V