Аннотация. Современные научные исследования прогрессивно развиваются, обещая наличие новых результатов. Одним из них является открытие и популяризация физики резонансных ядерных реакций в энергетическом плане. Особенностью данного раздела физики ядерных реакций является то, что возвращается вопрос об эффективности обычных экзо-энергетических ядерных реакций при проведении на ускорителях.
Ключевые слова: монохромотизация, резонансные ядерные реакции, ядерная физика, ускоритель заряженных частиц.
Annotation. Modern scientific research is progressing progressively, promising new results. One of them is the discovery and popularization of the physics of resonant nuclear reactions in the energy plan. The peculiarity of this section of nuclear reaction physics is that the question of the effectiveness of conventional exo-energetic nuclear reactions when carried out on accelerators returns.
Keywords: monochromatization, resonant nuclear reactions, nuclear physics, charged particle accelerator.
As is known, nuclear reactions are exo- and endo-energetic in nature, which divides them into categories according to the absorption and release of energy during the passage of the energy itself, due to the difference in the masses of the initial and resulting particles. At the same time, if the energy characteristics of these reactions were preserved, then the situation related to the number of interacting particles along the specified reaction channel becomes a big question, because any other interaction can also take place, due to the probabilistic nature of the behavior of such processes.
But as it turned out, the increase in the number of particles involved in the interaction increases when their energy approaches certain values resonances, which are already more precisely defined today. But one aspect remained quite interesting and this is the question of the approximation of energy to a certain limit the Coulomb barrier of the nucleus. Indeed, this barrier is not large in its dimensions, moreover, there is an additional energy spread due to ionization, which, fortunately, can already be calculated more accurately, for this reason, if we take into account all the ionization losses of the target substance, as well as the Coulomb barrier, as a result, the particle will have a sufficiently small nuclear gap energy. Here it is appropriate to recall the theory of dualism, according to which each particle is also a wave, and since the energy of the particle in the nucleus becomes minimal, its wavelength begins to grow, creating opportunities for interaction directly with the nucleus, excluding other probabilistic cases, which include the tunneling effect or scattering with elastic collision.
It seemed that this was not an effective procedure, since initially it was necessary to at least get into the Coulomb barrier itself, but due to sufficient beam density, as well as the effect of a monochromotizer, a theoretical result was obtained that greatly increases the efficiency of the entire reaction. For comparison, with only a boron-proton reaction with the release of 3 alpha particles on a thin 13 micron target, the effective cross-section of the nuclear reaction increases sharply and 99.999972% of all particles interact even at low currents, for a beryllium-proton-lithium reaction with the same alpha particles, this indicator is almost 100%, with the necessary accuracy. But there are also reactions with low efficiency, for example, proton-lithium-6 reactions with two alpha particles has an efficiency of only 65.53%, but at the same time having a large energy output.
The monochromotizer, which was mentioned earlier, is a device that separates a beam in a magnetic field by energy, after which a nano-structural substance a carbon mesh falls in its path, between the walls of the tubes of which there is a thin layer of a dielectric element or compound. At the same time, the induction vector of such an installation varies by a value of the order of 0.1 T and it can be noted that when the beam is deflected, a spectrum with a width of 0.327 mm is observed, while the wall thickness is measured in tens of nanometers, when the diameter of one inner tube is 0.572 microns, and the outer one is 0.636 microns. Losses at the same time exist and due to the "impact" on the walls of the tubes, up to 12.5% of the total number of charges is consumed.
But the energy accuracy in this case increases, so if for the SOKOL-2 accelerator at energies of 2 MeV, the accuracy was 5 keV, and for modern accelerators, more often at an energy of 20 MeV, the accuracy was 1 keV, then for an accelerator with a monochromotizer at that energy of 20 MeV, an accuracy of up to 50 MeV can be achieved, which it can even be considered the top of the unattainable, but even in spite of this, as the works show, these are quite achievable values, but for experimental verification, cooperation has already been established on the part of the company-the author of this project, OOO "Electron Laboratory" and the Scientific School "Electron" with the "Research Institute of Electro-Physical Equipment" "D. V.NIIEFA. Efremov", as well as with such organizations as the Scientific Research Institute "Physics of Semiconductors and Microelectronics" at the National University of Uzbekistan, Ferghana State University, Ferghana Polytechnic Institute, the State Unitary Enterprise "Yashil-Energia" at Ferghana State University, the Ferghana branch of the Tashkent University of Information Technologies and other organizations.
In the future, when conducting a successful series of experiments, much attention will be paid to the analysis of energy characteristics and resonances on light, heavy and superheavy nuclei at the specially created Research Laboratory of Physics of Resonant Nuclear Reactions at OOO «Electron Laboratory», in which we wish them good luck on the way to improving knowledge about the microcosm and its wonders of modern human society.
Used literature
1. Rumi R. F. The use of new nanostructure methods allowing to increase the monochromaticity of the beam during acceleration. All sciences. 7. Electron Scientific School, Publishing solutions. Ridero, 2022. pp. 15-25.
2. Aliyev I. H., Karimov B. H. Course of physics of charged particle accelerators. Study guide. [B.M.]: Scientific school "Electron", Publishing solutions. Ridero, 2022. 203 p.
3. Aliev I. H. New parameters for nuclear reactions to be carried out on an accelerator of charged particles of the LCC-EPD-300 type. The Electron project. Monograph. [B.M.]: Scientific school "Electron", Publishing solutions. Ridero, 2022. 498 p
. 4. Aliev I. H., Sharofutdinov F. M. The use of accelerators and phenomena of collisions of elementary particles with high-order energy for generating electrical energy. The Electron project. Monograph. [B.M.]: Scientific school "Electron", Publishing solutions. Ridero, 2021. 594 p.
5. Aliyev I. H. On a heuristic idea about the emergence of a new energy technology for obtaining energy from resonant nuclear reactions. All sciences. 1. Electron Scientific School, Publishing solutions. Ridero, 2022. pp. 13-18.
6. Karimov B. H. A general idea of the LCC-EPD-20 accelerator. All sciences. 1. Electron Scientific School, Publishing solutions. Ridero, 2022. pp. 18-23.
7. Zhalolov B. R. Implementation and scientific publications on the Electron project. All sciences. 1. Electron Scientific School, Publishing solutions. Ridero, 2022. pp. 2328.
STUDIES OF THE EFFECT OF gamma RADIATION AND LASER IRRADIATION ON THE KINETIC COEFFICIENTS OF POLY-CRYSTALLINE FILMS OF NARROW-BAND SEMICONDUCTORS
UDC 548
Yusupova Dilfuza Aminovna
Candidate of Physical and Mathematical Sciences, Associate Professor of the Faculty of Physics and Technology of Fergana State University
Ferghana State University, Ferghana, Uzbekistan
Аннотация: В работе приведены результаты исследования влияния лазерного излучения на кинетические характеристики поликристалли-ческих пленок узкозонных полупроводников халькогенидов свинца и висмута. Приведены результаты измерений проводимости, концентрации дырок и коэффициента термоЭДС в пленках под воздействием лазерных импульсов.
Ключевые слова: поликристаллическая пленка, лазерное излучение, халькогениды свинца и висмута, проводимость, концентрация носителей, коэффициент термо-ЭДС.
Abstract: The paper presents the results of a study of the effect of laser radiation on the kinetic characteristics of polycrystalline films of narrow-band semiconductors of lead and bismuth chalcogenides. The results of measurements of conductivity, hole concentration and thermal EMF coefficient in films under the influence of laser pulses are presented.
Keywords: polycrystalline film, laser radiation, lead and bismuth chalcogenides, conductivity, carrier concentration, thermo-EMF coefficient.
Laser processing of thin films deposited on a substrate is used to form film elements widely used in instrumentation and microelectronics. Laser processing of thin films is characterized by high accuracy and locality, non-contact, good controllability and in most cases sufficient performance. In the modern technology of semiconductor devices, methods of processing materials using ionizing radiation are becoming increasingly important [1]. Special attention is paid to the modification of the properties of layers under the action of short laser pulses, when, along with ordinary thermal heating of films, the influence of factors having a non-thermal nature is possible.
The physical mechanisms of action of laser radiation on thin films are in many ways similar to the effect of radiation on massive materials, but they have some features.
This paper presents the results of studies of the effect of g-radiation and laser irradiation on the kinetic coefficients of polycrystalline films of narrow-band semiconductors. The objects of research were polycrystalline layers of lead and bismuth chalcogenides and their compounds obtained by thermal vacuum condensation under various technological conditions. The substrates were quartz, polyimide (PM-1) and mica. The thickness of the obtained films was 0.34 microns. The films were irradiated with Co60 g-quanta and an industrial GIG-1M laser (D=15J, tim =50 ns) in air and in vacuum. Measurements of electrical conductivity, Hall coefficient and thermal EMF were carried out.
Electron microscopic studies have shown that with an increase in the condensation temperature, the size of the crystallites increases. When exposed to laser pulses of Pb0.8Sn0 films.2Te condensed at a temperature Tc = 373 K, it was found that at irradiation energies W > 0.15 J /cm2, there is a violation of the adhesion of the condensate with the substrate. In this regard, the irradiation energies were less than the specified value.
It should be noted that these energies are also less than the energy of the calculated value of the peak melting energy of films during laser processing in the nanosecond range, which is 02J/cm2 [1].
This paper presents studies of the effect of laser annealing (LO) on the kinetic properties of polycrystalline Pb0.8Sn0.2Te films obtained on polyimide and mica substrates by thermal vacuum technology at various condensation temperatures [2]. Irradiation was carried out in the modulated Q-factor mode with an industrial laser with a ruby emitter (l = 0.69 microns, tim = 50 ns). The energy density in the laser pulse was adjusted by focusing the light beam. The kinetic coefficients of the films were measured as a function of the number of laser pulse effects. At the same time, the structure of the initial and irradiated films was studied using scanning electron microscopy.
The conductivity s, the concentration of pH carriers and the coefficient of thermal emf a were measured depending on the number of laser pulses of films condensed at different substrate temperatures. The results of the conducted studies have shown that with an increase in Tc, the conductivity of films s increases, and the coefficient of thermal emf a decreases. When exposed to laser pulses, a decrease in s and a is observed in the films.
Electron microscopic studies of the films have shown that with an increase in Tc from 300K to 600K, the size of the crystallites increases from (5-6) 102 to 104 oA, and in these films with an increase in Tc, an increase in s and a decrease in a are observed.
Noticeable structural changes in LO were observed in films obtained on mica at Tc = 570K, i.e. at higher condensation temperatures. Here, the growth of single-crystal fragments is detected, the size of which was many times larger than the size of the crystallites in the original non-irradiated condensates.
The processes responsible for crystallization phenomena, in our opinion, are partial melting of condensates under laser irradiation (partial, since the energy in the pulse is less than the melting threshold) and shock crystallization (accelerated crystallization in the solid phase).
The nature of the change in the concentration of holes in Vi2SbxTe3 films at g-irradiation (Co60 source, intensity 103P/s) in freshly deposited films and a film pre-annealed in air at 420 K for 3 hours, in which the concentration of holes before annealing coincided with the initial concentration of holes, is given.
The following patterns were noted:
1. In samples with initial values of the concentration of holes p ~ 8 1018 cm-3, g irradiation leads to their monotonous increase with an output at Fd > 108P for saturation (curve 1); at 1019
2. At p> 5x1019 cm-3, with an increase in Fd, a decrease in concentration is observed with a decrease in the intensity of the process as the Fd increases (curve 3); in the same films, after thermal annealing, leading to a decrease in concentration, the process of decreasing concentration with an increase in Fd also slows down.
To explain the observed phenomena, it is necessary to accept the following. In technological regimes that provide a high concentration of holes, along with anti-structural defects, tellurium vacancies are formed in films [3]. Under g-irradiation, two processes are responsible for changes in the concentration of holes:
a) radiation-stimulated diffusion of antistructural atoms along vacancies with the displacement of the latter to the effluents the boundaries of crystallites and dislocations;
b) displacement of tellurium atoms into internodes.
The intensity of the first process is proportional to the concentration of vacancies and is more energetically advantageous relative to the second process. The first process is accompanied by a decrease in the number of acceptors, and the second by an increase, therefore, depending on the initial concentration of tellurium vacancies in films, two types of changes in the concentration of holes at g irradiation are possible, which is observed experimentally. The output of the p (Fd) dependence on saturation corresponds to the establishment of equilibrium in the course of both processes.