Electrophysical Characteristics Research Articles

Simulation of silicon conical field effect GAA nanotransistors with stack SiO2/HfO2 dielectric of gate

The issues of modeling the electrophysical characteristics of a silicon conical field effect GAA nanotransistor are discussed. An analytical model of the drain current of a transistor with a fully enclosing conical gate with a stack sub-gate oxide SiO2/HfO2 has been developed, taking into account the effect of the charge of the interphase trap at the Si/SiO2 interface. To simulate the potential distribution in a conical working area under the condition of constant trap density, an analytical solution of the Poisson equation was obtained using the method of parabolic approximation in a cylindrical coordinate system with appropriate boundary conditions. The potential model was used to develop an expression for the GAA drain current of a nanotransistor with a stack gate oxide. The key electrophysical characteristics are numerically investigated depending on the density of traps and the thicknesses of SiO2 and HfO2 layers.

Complex Diagnostics of Silicon-on-Insulator Layers after Ion Implantation and Annealing

A technology was developed for activating ion-implanted dopants in silicon-on-insulator layers at a low annealing temperature (600°C) using the pre-amorphization technique of a silicon device layer. In the case of phosphorus implantation, silicon was amorphized directly by dopant ions. In the case of boron implantation for pre-amorphization, the layers were preliminary irradiated with argon or fluorine ions. Complex diagnostics of the implanted layers was carried out using secondary ion mass spectrometry, X-ray diffractometry and small-angle X-ray reflectometry. The combination of methods made it possible to characterize the impurity distribution, the degree of silicon crystallinity, the layer thicknesses, and the interface widths in structures. The results of diagnostics of the structure and composition correlate well with calculations in the SRIM software package and the electrophysical characteristics of the layers after annealing. It was shown that the use of argon for pre-amorphization of silicon interfered with the recrystallization process and did not make it possible to achieve acceptable electrical characteristics of the doped layer. Amorphization with phosphorus and pre-amorphization with fluorine during boron implantation allowed obtaining the required values of the resistance of the doped layers after annealing at a temperature of 600°C. The use of a complex approach made it possible to optimize the modes of amorphization, ion doping, and annealing of silicon-on-insulator structures at low temperatures, necessary for the creation of light-emitting device structures based on silicon-germanium nanoislands.

Current Transport Mechanisms and Electrophysical Characteristics of the 4H-SiC p-n Junctions Formed by Aluminum Diffusion

In this paper, the electrophysical characteristics of the 4H-SiC p-n junction created by low-temperature diffusion of aluminum were studied. Current-voltage (I-V) characteristics are analysed, and the current transport mechanisms in 4H-SiC p-n junctions are discussed. It is shown that at low forward bias voltages, the generation–recombination mechanism dominates, and the I-V characteristics at voltages U > 3.0 V obey the linear law. At reverse biases, the dominant mechanism of current transfer is limited by the space charge.

Influence of electrophysical characteristics of plasma electrolytic treatment of 16MnCr5 structural alloy steel on structural and phase changes in the surface and its tribological properties

The possibility of using plasma electrolytic technologies for surface treatment of 16MnCr5 steel in order to increase its wear resistance is shown. The influence of electrophysical characteristics of plasma electrolytic treatment on structural-phase changes of the surface and its tribological properties is studied. A comparison of anodic and cathodic variants of diffusion saturation, as well as subsequent polishing on the results of surface modification is carried out. The complex effect of surface layers strengthened above 1100 HV, including iron carbide and nitride, martensite and retained austenite, to a depth of up to 250 μm with the preservation of a viscous core and the formation of a relatively homogeneous surface with reduced roughness on increasing wear resistance has been revealed. The features of tribological behavior of surfaces formed under different electrophysical parameters of processing, mainly related to the difference in surface microrelief, are shown. The correlation of the Kragelsky-Kambolov criterion as a complex assessment of surface roughness with its wear resistance is shown. The influence of changes in sliding speed and friction load on the occurrence and development of leading processes that determine the intensity and nature of destruction of friction surfaces is established.

Solid‐State Processing of Nascent Disentangled UHMWPE Reactor Powders Mixed with Carbon Nanoparticles

AbstractAspects of solid‐state processing of nascent disentangled ultra‐high‐molecular‐weight polyethylene (UHMWPE) powders of different syntheses mixed with electrically conductive carbon nanoparticles (NPs) of various types are studied. Effect of multiple parameters of the processing procedures on the electrophysical characteristics of the composite samples is investigated. Such parameters include time of preliminary ultrasonication (US) of NPs, time of US of UHMWPE/NPs mixtures, molding time, temperature, and pressure, deformation degree, etc. It is observed that by selecting optimal values of such parameters it is possible to obtain samples of composites with an extremely segregated structure made of the NPs, with NPs distributed evenly on the surfaces of the compacted UHMWPE powder particles. This ensures high levels of conductivity at very low values of NPs content. The segregated structure is retained when the composites are strengthened using the solid‐state uniaxial shear deformation process. While conductivity of most of the composites filled with various types of NPs monotonously decreases with the deformation ratio, conductivity of the composites filled with exceptionally long double‐walled carbon nanotubes is maintained. The processed oriented composites are also characterized by high EMR shielding properties, as well as interesting temperature dependencies of the electrical conductivity.

Electrophysical characteristics of film based on 2H-5,10,15,20-tetrakis(para-aminophenyl)porphyrin

Electrophysical characteristics of film based on 2H-5,10,15,20-tetrakis(para-aminophenyl)porphyrin

Electrophysical Characteristics of Acrylonitrile Butadiene Styrene Composites Filled with Magnetite and Carbon Fiber Fillers.

With the rapid development of wireless communication technologies and the miniaturization trend in the electronics industry, the reduction of electromagnetic interference has become an important issue. To solve this problem, a lot of attention has been focused on polymer composites with combined functional fillers. In this paper, we report a method for creating an acrylonitrile butadiene styrene (ABS) plastic composite with a low amount of conductive carbon and magnetic fillers preparation. Also, we investigate the mechanical, thermophysical, and electrodynamic characteristics of the resulting composites. Increasing the combined filler amount in the ABS composite from 1 to 5 wt % leads to a composite conductivity growth of almost 50 times. It is necessary to underline the temperature decrease of 5 wt % mass loss and, accordingly, the composite heat resistance reduction with an increase in the combined filler from 1 to 5 wt %, while the thermal conductivity remains almost constant. It was established that electrodynamic and physical-mechanical characteristics depend on the agglomeration of fillers. This work is expected to reveal the potential of combining commercially available fillers to construct effective materials with good electromagnetic interference (EMI) protection using mass production methods (extrusion and injection molding).

Негативний диференціальний опір і спектральні характеристики вихідних та опромінених електронами (з Е = 2 МеВ) світлодіодів GaAs1-xPx

The electrophysical and radiation characteristics of the original and irradiated electrons with E = 2 MeV GaAsP light emitting diodes were studied. The results of measurements of current-current characteristics in the range of 77 - 300 K are given. In the range of 180 - 77 K, a region of negative differential resistance was detected. The main characteristic parameters of light emitting diodes radiation are determined. The consequences of the effect of radiation defects on the emissivity and quantum yield of the studied structures are discussed.

Sr-doped carbon matrices for use as electrodes in autonomous electrical energy sources

Relevance. The need to create new safe energy sources that can meet the needs of production and medicine where the use of traditional energy sources is impossible or unprofitable. Such sources may include radioisotope power sources, in which energy production is ensured by the natural decay of radionuclides. The most important components of current sources such as supercapacitors are electrode materials, the characteristics of which determine the electrophysical characteristics of radioisotope sources. This work proposes a method for synthesizing a carbon matrix doped with Sr for use as electrodes of radioisotope power sources. Aim. Development, mastery and optimization of a method for synthesizing electrodes of radioisotope power sources based on carbon materials doped with the Sr-90 radioisotope. Objects. Carbon material doped with a radioisotope simulant Sr-90 (Sr stable). Carbon matrices were obtained by carbonizing a resorcinol-formaldehyde resin doped with a stable strontium salt. Methods. Scanning electron microscopy, low-temperature adsorption-desorption of nitrogen, cyclic voltammetry, galvanostatic charge-discharge, impedance microscopy. Results. A carbon matrix doped with a stable strontium isotope was synthesized by the method of semi-carbonization followed by physical activation with carbon dioxide. The structure, porosity and electrochemical characteristics of the material were studied. It was established that physical activation has a positive effect on the development of the specific surface area and mesoporosity of the samples of the synthesized matrix, as a result of which its electrochemical characteristics are improved. The method of physical activation is proposed as the most preferable for the synthesis of a carbon matrix doped with strontium isotopes for use as electrodes of radioisotope power supplies.

Ionic Liquids as Modifiers for the Electrophysical Characteristics of Fillers and a Polymer Material

Ionic Liquids as Modifiers for the Electrophysical Characteristics of Fillers and a Polymer Material

Электрофизические и температурные характеристики тонких слоёв квантовых точек Ag2S

В работе представлено исследование электрофизических свойств тонких плёнок коллоидных квантовых точек сульфида серебра (КТ Ag2S/SiO2) и квантовых точек сульфида серебра, декорированных плазмонными наночастицами золота (КТ Ag2S/SiO2/Au). Проведено исследование температурных зависимостей проводимости в диапазоне температур от 300 до 360 К. Были получены значения энергии активации из линейных аппроксимаций вольт-амперных характеристик в координатах Аррениуса. Показано, что декорирование КТ Ag2S/SiO2 плазмонными наночастицами золота приводит к увеличению ширины запрещенной зоны с 0.29 до 0.89 эВ. В работе рассчитан фактор идеальности и определены основные механизмы проводимости представленных тонкоплёночных структур. Показано, что декорирование КТ Ag2S/SiO2 наночастицами Au приводит к изменению типа проводимости. Согласно модели Мотта-Герни рассчитана подвижности носителей заряда.

Comparative studies of GaN, n-GaN and n+-GaN contact layers on GaN/c-Al2O3 virtual substrates synthesized by PA MBE

An approach to create ohmic contacts to GaN layers without using the high-temperature annealing procedure is described in the paper. The results of comparative studies of structural, morphological, optical, and electrical properties of undoped GaN and silicon-doped n-GaN and n+-GaN doped contact layers are presented.The contact layer technology can be successfully realized using a plasma-assisted molecular beam epitaxy (PA MBE) setup of industrial type, where due to characteristic design features, the growth of nitride AIIIN compounds occurs using small streams of activated nitrogen, which significantly limits the possibility of varying the technological parameters.For the first time it is demonstrated that using the proposed technology for the creation of post-grown GaN, n-GaN and n+-GaN contact layers to GaN/c-Al2O3 virtual substrates in Ga-enriched conditions of epitaxial PA MBE growth at relatively low temperatures Ts = 700oC an effective filtration of dislocations threading from the buffer GaN layer of the virtual substrate formed by MOCVD can be realized.Calculations of in-plane εxx and out-of-plane εzz deformations, as well as residual biaxial stresses based on X-ray diffraction and Raman microspectroscopy data indicate at high structural quality of the formed contact layer regardless of the silicon doping level. At the same time PA MBE contact layers GaN, n-GaN and n+-GaN demonstrate close optical properties (refractive index and photoluminescence) in a wide range (400–850 nm), as well as minimal influence of defects associated with the formation of silicon clusters at high doping levels.The contact resistance reduced to the pad width determined using the transmission line method for the structure with n+-GaN contact layer was of ∼0.11 Ohm*mm and ∼0.5 Ohm*mm for n-GaN. Note that electrophysical characteristics of n-GaN and n+-GaN contact layers do not degrade under high-dose exposure of high-energy X-ray irradiation.The technique developed in our work to create ohmic contacts to GaN layers, as well as the obtained experimental results, have important implications for understanding the physics of AIIIN nanoheterostructures and will contribute to their potential applications in their fabrication.

Analysis of the State of Moisture Control to Ensure and Regulate the Quality of Grain and Grain Products

The article discusses the methods for determining the maturity of grain and describes its behavior during harvesting, to optimize the selection of the grain moisture state, discusses the requirements for the choice of measurement method and the design of moisture control measuring devices, as well as its high accuracy and the possibility of measuring from field conditions, collection, storage, transportation, and industrial processing and release of finished products of granular materials. The purpose of the study is to improve the efficiency of control and management of complex technological processes and moisture control devices for granular bulk materials of plant origin through the development of systems for automatic and automated control of the electrophysical characteristics of grain products and to increase the reliability of quantitative and qualitative assessments of production and technological measurement information. To achieve this goal, it is necessary to conduct analytical and experimental studies of the possibility of creating an express method for controlling the moisture content of grain and products of their industrial processing and the development of a moisture meter for automated control of raw material parameters during acceptance and storage at grain processing enterprises. The article discusses the scientific and methodological foundations for measuring the electrophysical characteristics of grain products of agricultural production and the implementation on this basis of the functional subsystem of information support by the Automated Process Control System for Controlling the Mass Ratio of Moisture of Plant Origin Materials. A critical analysis of the current state of the theory and practice of automatic control of electrophysical characteristics of grain products and the identification of the trend of their further development and improvement are carried out. A mathematical model of the interaction of a high-frequency field with a granular material has been constructed, where the influence of the elastic properties of the grain on the electrical characteristics of the electromagnetic wave, which distinguishes its behavior in the field of a high-frequency wave from many other dielectrics, has been substantiated, and the influence of a large number of various disturbing factors has been studied, often the measurement results cannot be applied in the control of the technological process due to the uneliminated error, which is the cause of inaccurate information. Primary measuring transducers of electrophysical parameters of grain products are proposed, and their mathematical models are considered. A functional scheme of the measuring device based on the dielcometric method of moisture control of grain and granular materials has been developed, and metrological characteristics have been given.

Study of adsorption of household gas molecules on electrophysical properties of porous silicon

Purpose. This research comprehensively investigates the adsorption of household gas molecules on porous silicon surfaces and its impact on the electrophysical properties of the material. The primary aim is to understand how the adsorption process influences the electrical conductivity and capacitance of porous silicon. Methodology. The study employs various electrophysical analysis methods to measure changes in the material's conductivity and capacitance caused by gas adsorption. Furthermore, the research explores optimal conditions for detecting household gas and establishes the correlation between the degree of adsorption and alterations in electrophysical parameters. Originality. The research contributes novelty by not only revealing increased conductivity due to adsorption but also significant changes in capacitance, providing a foundation for developing efficient gas sensors. Additionally, the article discusses the potential applications of porous silicon in developing novel materials for gas sensors to detect various airborne pollutants. Results. In addition to the previously mentioned findings, the article highlights the results of experiments studying the influence of different concentrations of household gas on the electrophysical characteristics of porous silicon. This insight refines optimal parameters for the effective detection of gas pollutants. The research also discusses the applicability of the results in producing environmentally friendly and highly efficient sensor systems. Practical Value. The obtained conclusions deepen our understanding of the interaction between porous silicon and household gas, crucial for advancing gas sensor technologies. The study opens broad possibilities for applying porous silicon in highly sensitive and reliable gas sensors for diverse practical applications, including safety monitoring and air quality control in industrial and domestic settings. The practical implications extend to the development of real-time, eco-friendly sensor systems.

ИМПЕДАНСНЫЙ АНАЛИЗ ПРОЦЕССОВ ПЕРЕНОСА ЗАРЯДА В СТРУКТУРЕ МЕТАЛЛ/ПОЛИМЕР/МЕТАЛЛ

The reaserch is devoted to the experimental study of charge transfer processes in thin films of an electroactive polymer from the class of polyarylene phthalides – poly (diphenylene phthalide). The method of impedance analysis of thin polymer films was used in this work. The material is quite well studied using other methods, such as thermally stimulated methods, optical spectroscopy, etc. However, frequency measurements were carried out mainly only in the field of determining capacitance-voltage characteristics. And since the polymer is electroactive, we should expect to identify features associated with charge transfer in the alternating field mode. In this regard, the work carried out an impedance analysis of thin films of poly (diphenylene phthalide) in the frequency range from 0.1 to 106 Hz. Typically, in impedance analysis, in addition to an ac field, a small DC bias voltage is applied to the metal/polymer/metal structure. This makes it possible to obtain data on surface polarization, charge carrier mobility, and the Maxwell-Wagner effect in the case of studying multilayer films. However, taking into account the electrical activity of the studied material, even impedance analysis in an alternating field, but with an effective voltage range from 0.1 to 10 V, made it possible to evaluate some of the electrophysical characteristics of the behavior of thin films. It was found that the slope of the impedance curve depends on the mechanism of transport of charge carriers in the polymer film. As the voltage increases from 0.1 to 10 V, an increase in the slope of the graph is observed. With an increase in the magnitude of the effective voltage, a transition occurs from the ohmic to the injection mechanism of transport of charge carriers limited by traps. When reaching 2 V, a mode of complete filling of the traps is observed, as a result of which an increase in voltage ceases to affect the slope of the frequency response. The dependence of the transition frequency fc on voltage has been plotted. This frequency corresponds to the transition from the predominance of the active to the reactive component of the impedance. Here, an exponential dependence on the magnitude of the applied voltage is observed, which also indicates the dependence of the mechanisms of transport of charge carriers in the polymer film on voltage (electric field).

Variations in the characteristics of low-voltage logic gates based on vertical silicon nanotransistors with a conical channel

The issues of numerical simulation of fluctuations in the electro-physical characteristics of low-voltage logic gates based on silicon vertical nanotransistors with a surrounding gate with a conical geometry are discussed. Instrumentation and technological models of n- and p-types of conductivity of conical nanotransistors have been developed for the case when the conical working area is set as follows. On the source side, for a large diameter, the condition for suppressing short-channel effects is not fulfilled, and on the drain side, for a small diameter, it is fulfilled. Such transistor structures in the control voltage range from 0 to 0.6 V are characterized by a higher transistor current, a low leakage current and a slope of the subthreshold characteristic close to the theoretical limit. Prototypes of transistors with optimal parameters for the synthesis of logic gates with a gate length of 25 nm and a working area diameter ratio of 8.5/10 nm have been selected. The fluctuation range of the drain current is distributed according to the normal law for both types of transistors with an average of 12.25 µA for the n-type and 6.5 µA for the p-type and a standard deviation of 19.3. The total spread is 3.06 µA and 1.45 µA, or 25% and 22%, respectively. To offset the influence of the considered mechanisms, it is recommended to limit the level of doping of the drain/source regions and use relatively large cross-sections of the working area from the range of possible ones. This will ensure stable electro-physical characteristics of transistors with high parry of short-channel effects. An instrument-technological model of an inverter based on vertically arranged n- and p-type transistors with an optimized diameter ratio has been developed. Variations of electro-physical characteristics in the range of control voltages 0...0.6 V and a clock frequency of 20 GHz are numerically investigated. In all cases, the prototypes demonstrate picosecond delays and low power consumption. The valve model predicts a general fluctuation of switching times of 18% at average values of 1.6 and 0.8 ps, respectively, active power of 16% at an average value of 0.2 µW and static power of 11% at an average value of 0.7 pW. The results of the study can be used in the design of digital circuits to expand the SOA zone.

Structural and electrophysical properties of nanoporous carbon materials obtained from apricot pits

The dependencies of the electrophysical characteristics of nanoporous carbon material (NCM) on the compaction degree of its particles have been investigated in the presented study. It has been found that the maximum value of the electrical conductivity is achieved at a pressure of 2.5 MPa. Furthermore, it has been revealed that the formation of O-compounds on the surface of the studied materials leads to a decrease in electrical conductivity. The correlation between structural-adsorption and electrical-conductive properties of NCMs has been established. Moreover, it has been demonstrated that an increase in the amount of potassium hydroxide results in a decrease in electrical conductivity due to the breakdown of small carbon particles and an increase in contact resistance, while the specific surface area enlarges due to the development of porosity and an increase in the total pore volume.

Electrophysical Characteristics of $c$BN–NbN Composite Ceramics Doped with Al$_{2}$O$_{3}$, Si$_{3}$N$_{4}$, and SiC

Electrophysical Characteristics of $c$BN–NbN Composite Ceramics Doped with Al$_{2}$O$_{3}$, Si$_{3}$N$_{4}$, and SiC

Characterization of a Heterojunction Silicon Solar Cell by Means of Impedance Spectroscopy.

Impedance spectroscopy provides relevant knowledge on the recombination and extraction of photogenerated charge carriers in various types of photovoltaic devices. In particular, this method is of great benefit to the study of crystalline silicon (c-Si)-based solar cells, a market-dominating commercial technology, for example, in terms of the comparison of various types of c-Si devices. This study investigates the dark and light electrophysical characteristics of a heterojunction silicon solar cell fabricated using plasma-enhanced chemical vapor deposition. The measurements are performed at various applied biases, enabling the determination of complex resistance, characteristic time, capacitive response and impurity concentration within the semiconductor junction and to correlate them with the device performance. In addition, the impedance spectra of the studied cell were investigated as a function of temperature. Studies of the frequency and temperature dependences of capacitance do not reveal a significant presence of thermally activated centers of free carrier capture, concomitant with a very small value of the activation energy extracted from an Arrhenius-type analysis. This leads to a conclusion that these centers are likely not impactful on the device operation and efficiency.

Numerical and analytical solution of temperature distribution in foamed soy suspension during vacuum microwave drying

Objective. Technologies of vacuum dehydration of solutions in the microwave field are constantly developing in the direction of increasing the energy efficiency of the drying process and reducing the cost of target products. This scientific direction fully applies to vacuum microwave drying of soy suspension in a foamed state. In this regard, the most important task is to improve mathematical modeling, which provides significant assistance in the study of heat and mass transfer processes occurring in vacuum dryers with microwave power supply; in the design of new installations and the development of effective modes of their operation; the development of optimal modes of vacuum drying foamed soy suspension, taking into account thermophysical and electrophysical characteristics. Method. The research is based on computer simulation methods. Result. Using the results of previous studies, a mathematical apparatus was obtained for finding the temperature in a foamy product during vacuum microwave drying. Its difference from existing mathematical models lies in the possibility of using simple methods for analyzing differential equations with fewer unknown variables. A method of numerical and analytical solution of a mathematical model of the process of vacuum microwave drying of foamed suspension is proposed. Experimental verification showed quite satisfactory convergence of the simulation results with an error of 10-12%. Conclusion. The study of numerical methods for solving the formulated problem makes it possible to determine the temperature at any point of the soybean suspension, taking into account the thermophysical and electrical characteristics of the suspension in a wide range of operating parameters.