Ionization equilibrium in a highly imperfect smoke plasma

The ionization equilibrium in a heterogeneous strongly nonideal smoky plasmas containing condensed particles and an easily ionized addition of cesium atoms in the gas phase is considered. To determine the charges of particles, the nonlinear Poisson-Boltzmann equation was used, and for the ionization of atoms of the gas phase, the Saha equation taking into account the effect of the displacement of the ionization equilibrium. The dependences of the concentration of electrons and particle charges, as well as the interface between the regions of positive and negative charges of particles, on the concentration of cesium atoms and the concentration of aluminum oxide particles are obtained.

Chemical method for reducing the concentration of electrons in the plasma behind a strong shock wave

In this paper it is shown theoretically using computational methods that the addition of phosphorus-containing substances during the shock wave leads to a decrease in the concentration of electrons at temperatures in the front of shock wave 300 K and behind it of 6000 – 13000° K. Shock wave Mack number is high up to 14. The density is about of 0.35 – 0.7 kg/m3.

Analysis of the system of current stabilization of the radiation power of glow-discharge lasers

The article analyzes the transfer function of the discharge gaps of glow discharge lasers. The transfer function in this case shows how a change in the discharge current leads to a change in the concentration of electrons in the positive column, which are an energy source for the excitation of laser levels. Based on the analysis, the characteristic time constants of the transfer function were calculated for the main types of glow discharge lasers.

Влияние сильного межузельного кулоновского взаимодействия на топологические свойства сверхпроводящей нанопроволоки

For superconducting nanowire with the pairing of extended s-type symmetry, Rashba spin-orbit interaction in a magnetic field, the influence of strong intersite charge correlations on single-particle Majorana excitations is analyzed. This problem is investigated on the basis of the density matrix renormalization group numerical method. It is shown that with an increase in the repulsion intensity of electrons located at the neighboring sites, two subbands emerge in the lower Hubbard band of the open system. Based on calculations of the Majorana polarization and degeneracy of the entanglement spectrum, it was found that a topologically nontrivial phase with one edge state survives at the edge of each of the subbands where the concentration of electrons or holes is minimal.

Комплексное исследование кластеров радиационных дефектов в GaAs-структурах после нейтронного воздействия

The results of experimental studies of the electrical parameters and surface morphology of GaAs structures of ring and circular Schottky diodes before and after irradiation with ~ 1 MeV neutrons are presented. Bulk radiation defects were revealed by atomic force microscopy (AFM). Based on the results of capacitance-voltage measurements, the concentration of electrons was determined and their mobility was estimated before and after irradiation. On the basis of the results obtained using a combination of these methods, a technique is proposed for determining the average sizes of the space charge regions of clusters of radiation defects.

Comparison between optical and electrophysical data on free electron concentration in tellurium doped n-GaAs

A theoretical model has been developed for determining free electron concentration in n-GaAs from characteristic points in the far infrared region of reflection spectra. We show that when determining free electron concentration one should take into account the pasmon–phonon coupling, otherwise free electron concentration will be overestimated. We have calculated electron concentration Nopt as a function of characteristic wave number ν+ which is described by a second order polynomial. Twenty-five tellurium doped gallium arsenide specimens have been tested for electron concentration using two methods, i.e., the conventional four-probe method (Van der Pau) and the optical method developed by us (the measurements have been carried out at room temperature). We have used the experimental results to plot the dependence of electron concentration based on the Hall data (NHall) on electron concentration based on the optical data (Nopt). This dependence is described by a linear function. We show that the data of optical and electrophysical measurements agree if the electron concentration is Neq = 1.07 · 1018 cm-3. At lower Hall electron concentrations, NHall < Nopt, whereas at higher ones, NHall > Nopt. We have suggested a qualitative model describing these results. We assume that tellurium atoms associate into complexes with arsenic vacancies thus reducing the concentration of electrons. The concentration of arsenic vacancies is lower on the crystal surface, hence the Nopt > NHall condition should be met. With an increase in doping level, more and more tellurium atoms remain electrically active, so the bulk concentration of electrons starts to prevail over the surface one. However with further increase in doping level the NHall/Nopt ratio starts to decrease again and tends to unity. This seems to originate from the fact that the decomposition intensity of the tellurium atom + arsenic vacancy complexes decreases with an increase in doping level.

About the correlation between the values of the VTEC ionosphere parameter on GNSS stations of Ukraine

Obtaining information about the spatial distribution of electronic concentration is a complicated task, since the highrise distribution profiles of the TEC parameter vary both in time and in longitude and latitude, and depend on the magnetic and solar activity. In this regard, it is relevant to study the characteristic quantitative parameters describing the dynamics of ionization of the atmosphere. The purpose of this work is to study the parameter of the ionosphere VTEC, namely the study of correlation links between this parameter at different GNSS stations, the distance between them ranges from 100 to 400 km. To solve this problem, ionfiles were first processed with VTEC parameter values ??at different stations, and their filtration was performed with the help of the Kalman filter. Next, the correlation coefficients between the values ??of the VTEC parameter are found pairwise for all GNSS stations under investigation. The analytical connection between the coefficient of correlation of VTEC parameters and the distance between GNSS stations is proposed. The obtained results allow to simulate variations and dynamics of changes in the concentration of electrons in space.

Piezotronic Effect of a Thin Film With Elastic and Piezoelectric Semiconductor Layers Under a Static Flexural Loading

We theoretically study the electromechanical behaviors of a laminated thin-film piezoelectric semiconductor (PS) composite plate with flexural deformation. The nonlinear equations for drift currents of electrons and holes are linearized for a small carrier concentration perturbation. Following the structural theory systemized by R. D. Mindlin, a system of two-dimensional (2D) equations for the laminated thin-film PS plate, including the lowest order coupled extensional and flexural motion, are presented by expanding the displacement, potential, and the incremental concentration of electrons and holes as power series of the plate thickness. Based on the derived 2D equations, the analytical expressions of the electromechanical fields and distribution of electrons in the thin-film PS plate with an n-type ZnO layer subjected to a static bending are presented. The numerical results show that the electromechanical behaviors and piezotronic effects can be effectively controlled by the external applied force and initial concentration of carriers. The derived 2D equations and numerical results in this paper are helpful for developing piezotronic devices.

PROGRAMMING 2-BIT PIN DIODE IN SYNOPSYS TCAD

The article is devoted to the modeling of a two-bit pin-diode. The possibility of programming opening time of the device based on the pin-diode is shown. The design consisting of a pin diode and two floating gates on the surface of i-region is considered. The addition of electrodes to the surface of the i-region makes it possible to regulate the concentration of electrons and holes within the larger limits in compare with the single-gate structure creating enriched and depleted are-as in the structure. Programming is carried out by applying the appropriate voltage to the control electrodes of the floating gates. It is shown that the charge generated on the floating gate changes characteristics of the i-region of the pin diode.The key elements of complex simulation of the two-gate pin diode are simulation of charge accumulation mechanism on the floating gate, simulation of pin-diode opening time and calibration of numerical model. Simulation is performed in Synopsys Sentaurus TCAD. Physical models describing traps and their parameters, particle tunneling, transport phenomena in dielectrics and amorphous films are used in simulation. As a result of modeling, the opening time dependences on size, floating gate location and floating gate charge magnitude are obtained.It is shown that the pin-diode 2-gate structures allow to change the opening time in a wider range than the single-gate ones. To program a large range of pin-diode opening times, it is 2 gate structure that is advisable to use. The obtained results indicate that it is possible to implement a two-bit programming pin-diode and expand its functionality.