Formation of Porous ZnO Nanosystems for Potential Use in Sensor Electronics

The semiconducting ZnO is a very promising material for applications in UV light emitters, optical de-tectors, solar cells, piezoelectric transducers, transparent electronics, gas sensors etc. It is known that physical properties, and as a result areas of applications, are strongly determined by morphology and size of the material’s structural elements. Therefore, the development of a technology that allows formation of nanoporous metal oxide structures with a high surface to volume ratio is of great interest nowadays. The aim of this work was to develop technology for selective formation of porous ZnO nanosystems and to de-termine the relationship between morphological characteristics of the layers obtained and their optical and electrical sensor properties with the aim of potential applications in optoelectronics and sensor electronics. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

Formation of Porous ZnO Nanosystems for Potential Use in Sensor Electronics

The semiconducting ZnO is a very promising material for applications in UV light emitters, optical de-tectors, solar cells, piezoelectric transducers, transparent electronics, gas sensors etc. It is known that physical properties, and as a result areas of applications, are strongly determined by morphology and size of the material’s structural elements. Therefore, the development of a technology that allows formation of nanoporous metal oxide structures with a high surface to volume ratio is of great interest nowadays. The aim of this work was to develop technology for selective formation of porous ZnO nanosystems and to de-termine the relationship between morphological characteristics of the layers obtained and their optical and electrical sensor properties with the aim of potential applications in optoelectronics and sensor electronics. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

Self-organization of plasma–condensate quasi-equilibrium systems

The steady-state regime of condensation under conditions close to the phase equilibrium is shown to be provided by the self-organization of the plasma–condensate system. This self-organization is associated with the fact that the presence of the plasma leads to a considerable increase in the energy of adatoms and, hence, in the temperature of the growth surface in the course of their condensation. The increase in the temperature is compensated by the desorption flow of adatoms responsible for the supersaturation. It is demonstrated that the proximity of the system to the phase equilibrium ensures the selective regime of condensation during which the adatoms are attached onto active centers of the growth surface, thus forming various three-dimensional structures. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/331

Formation of porous zinc nanosystems using direct and reverse flows of DC magnetron sputtering

The work is devoted to comparative analysis of two technological solutions for Zn nanosystems formation which have been implemented on the basis of direct-current magnetron sputtering. In the first case, conventional magnetron sputtering was used and direct flows were deposited on the substrate positioned in the front of a sputterer. In the second case, reverse flows were used and the substrate was located inside the magnetron sputterer. It has been shown experimentally, that the second technological approach gives more reproducible results as compared to the classical one. In addition, usage of the reverse flows leads to significant increase in the nanosystems deposition rates

Methods and tools of transient radiation registration for diagnostics of high-intensity electron beams

The general method of diagnostics of the transient radiation of ribbon-shaped and axially-symmetric electron beams of small section (0.1 mm) and high-power density (1–100 kW/sm2) is described. Selective analysis of various types of transient radiation detectors of type photo-camera, video-camera and digital photo-camera is carried out at first. Advantages and disadvantages of radiation detectors are pointed out to be taken into account at analysis of the object under investigation

Regularities of Structural and Morphological Changes of Nanosystems Based on Zn Condensates at their Oxidation in Air Atmosphere

Изучены закономерности структурно-морфологических изменений трехмерных сеточных наноси- стем Zn в процессе их окисления в атмосфере воздуха. Проанализирован фазовый и элементный со- став наносистем на разных этапах их медленного окисления. Показано, что переход от медленного к быстрому начальному разогреву наносистем до температуры дальнейшего полного окисления 350 °С подавляет формирование наростов ZnO на поверхности нитей. Предложен механизм формирования наростов ZnO на основании термодиффузионных процессов, стимулированных малой теплоемкостью нитей, развитой системой дефектов, а также возможным растрескиванием окисляемой поверхности нитей.Вивчені закономірності структурно-морфологічних змін тривимірних сіткових наносистем Zn в процесі їх окислення в атмосфері повітря. Проаналізовано фазовий і елементний склад наносистем на різних етапах їх повільного окислення. Показано, що перехід від повільного до швидкого початкового розігріву наносистем до температури подальшого повного окислення 350 °С пригнічує формування наростів ZnO на поверхні ниток. Запропоновано механізм формування наростів ZnO на основі термо- диффузійних процесів, стимульованих малою теплоємністю ниток, розвиненою системою дефектів, а також можливим розтріскуванням поверхні ниток, що окислюються.The regularities of changes in structure and morphology of Zn nanosystems with network morphology have been investigated during their oxidation in air atmosphere. The nanosystems phase and elemental composition have been analyzed on different stages of their gradual oxidation. It has been shown, that transition from slow to fast initial heating of the nanosystems up to the temperature of their full oxidation 350 °С suppresses nucleation of new ZnO crystals on the nanowires surface. The mechanism of new ZnO crystals formation is explained by thermal diffusion processes that appear due to the nanowires low thermal conductivity, by developed defect system and also by possible cracking of the nanowires surface during the oxidation process