This paper considers the problem of surface dipole ordering of thin polymer layers with nanometer range thicknesses. We have experimentally studied submicron dielectric films of electrically active polydiphenylenephthalide polymer composed of molecules that included a side phthalide group with a relatively large dipole moment. The interest to this polymer is caused by an abnormally high conductivity at the polymer/polymer interface which was previously associated with possible superficial ordering of the phthalide groups. Using the methods of piezoresponse force microscopy we have explored the surface of submicron films synthesized by centrifugation. We have detected a manifestation of spontaneous polarization indicating the ordering of dipoles. Also, in order to determine the bulk and surface contributions to the polarization of the films we have studied the polarization and relaxation in samples of different thicknesses. With a reduction of the thickness the piezoelectric response of the signal increases and electrically generated domains acquire ideal radial shapes. This confirms that the surface layers of the polymer film make the predominant contribution to orientation processes. Polarization switching occurs in the films, manifested by the change of the piezoelectric response signal contrast when fields of different polarity are applied. We use these surface phenomena to explain the unique electronic properties of the boundaries of polar organic dielectrics.

Cz growth of large diameter Ge single crystals has been studied. The crystals have been grown from the melt with various shapes of the crystallization front. The formation of dislocation low angle boundaries (LAB) has been analyzed. We have analyzed the formation of LAB in the as−grown Ge crystals taking into account the actual distribution of thermal tension in the crystal in the presence of radial and axial heat sinks. The behavior LAB−forming dislocations in the thermal tension field has been considered. We have analyzed the migration of these dislocations in the sliding planes and specified possible dislocation aggregation planes. The best results have been obtained for crystals in which the crystallization front was slightly concave towards the crystal. Thus, we have observed a uniform distribution of dislocations. As a result of the analysis we have determined the thermal conditions for growth of LAB free ingots. Experiments confirmed the compliance of model representations with real crystal growth conditions, and we have obtained Ge single crystals with a diameter of100 mmand more, with a low dislocations density and free from LAB.

We have studied the influence of dopant Y₂O₃ oxide (1 and 2 mol.%) on the phase composition, structure and electrical properties of the ZrO₂ — 9 mol.% Sc₂O₃ solid solution. We have shown that stabilization of ZrO₂ jointly with 9 mol.% Sc₂O₃ and 2 mol.% Y₂O₃ allows one to obtain transparent homogeneous crystals with a cubic structure which have a high phase stability. Mechanical grinding of these crystals did not lead to a change in the phase composition of the powders. The powders inherited the original structure of the fluorite crystals. All the test crystals had high microhardness and low fracture toughness. Increasing the concentration of Y₂O₃ in crystals led to the need to reduce maximum loads on the indenter that the sample could withstand without cracking. We have shown that the conductivity varies nonmonotonically with increasing Y₂O₃ concentration in the crystals. An increase in the Y₂O₃ content to 2 mol. % in the composition of the solid electrolyte reduces the conductivity of the crystals in entire temperature range which is caused with a decrease in carrier mobility due to increasing ion radius of the stabilizing ion.

This article discusses the possibility of increasing the efficiency of betavoltaic generators by using lithium niobate single−crystal bimorph as the piezoelectric transducer element. Existing betavoltaic alternating voltage generators consist of a piezoelectric cantilever and a  electron source, wherein the cantilever is a resilient member, for example silicon, to which a PZT ceramics piezoelectric element is connected. In this study we suggest changing the structure of the silicon cantilever with a piezoelectric element for a uniform cantilever which is a thin plate of bidomain lithium niobate single crystal. This increases the efficiency of converting mechanical vibrations to electrical power, Q of the system, and the stability of the working parameters, and furthermore significantly increases — up to several hundred degrees — the operation temperature range. We have considered in details the solution of the main task —formation of a bidomain structure in a thin lithium niobate plate. A method of the sample high−temperature annealing in a nonuniform electric field is proposed. The possibility of domain structure prediction on the basis of the developed model is shown. Samples with a domain boundary depth of 120—150 microns have been obtained, and we have shown that the clarity of the boundary depends on the voltage between the working cell strip electrodes and the external electrode. The method is effective for bidomain structure formation in plates of about 300 microns in thickness.

Promising absorbing materials include Ni—Zn−ferrites, as they quite intensively absorb electromagnetic waves in the 50 MHz to 1000 MHz frequency range. In this paper we have studied the electromagnetic properties of Ni—Zn ferrite absorbing materials obtained in different technological modes. We propose a model that allows one to evaluate the dielectric constant of the ferrite material depending on the parameters of the microstructure and electrical properties of grain boundaries. Influence of base composition and microstructure on the level of absorption of electromagnetic radiation by Ni—Zn ferrite absorbing materials has been found. An increase in Fe₂O₃ excess to 51 % has been found to shift the frequency interval of electromagnetic radiation absorption towards lower frequencies, and this effect can be explained by an increase in the dielectric and magnetic constants of ferrite. Introduction of excess Fe₂O₃ in step 2 of grinding proved to be more efficient. An increase in the sintering temperature to 1350 °C also provides for a shift of electromagnetic radiation absorption frequency interval towards lower frequencies, which can be explained by an increase of the dielectric and magnetic constants of ferrite and resonance frequency shift of domain walls due to the formation of a coarse−grained structure.

Molecular dynamic modeling of the deposition of a single ammonium molecule on the (111) surface of silicon has been carried out. We have used the process of parametric identification of interatomic interaction potentials for the atomic system being described. We have developed software for the molecular dynamic calculations that allows optimizing the geometry of the structures being considered and visualizing the results. To verify the results of molecular dynamic modeling we have carried out quantum mechanical calculations on a supercomputer. We have obtained the interatomic interaction potentials that allow deriving potentials suitable for further calculations during the modeling of the adsorption of an ammonium molecule on silicon surface. For example, they provide for a correct reproduction of the results of first−principle modeling of the interaction between an adsorbed nitrogen atom and silicon surface and the energy parameters of adsorption. Using the Tersoff potential with the parameters obtained as a result of parametric identification we modeled the position providing for the lowest total energy. This position is the most energetically favorable for an adsorbed atom.

It well−known that optical fibers have a «window of transparency » (1.5−3 µm) which is much wider than the spectra of the transmitted signals. For this reason there is some potential in transmitting signals using different, previously unused frequencies, in order to increase the economic efficiency of existing and new optical fiber lines. This may be the origin of the great interest to research into the creation of А²В⁶ and А³В⁵ semiconductor lasers doped with Cr²⁺, Co²⁺, Ni²⁺, Fe²⁺ and rare earth element ions. Theoretical and experimental studies in this field are usually focused on one type of semiconductor doped with one type of ion. With the appearance of the general theory of ligand structure environment of iron group ions (Co²⁺, Ni²⁺ and Fe²⁺) there is now a way to calculate the full matrix of luminescence parameters of iron group ions for the entire group of А²В⁶ semiconductors, in addition to conventional research methods. The results of research for Fe²⁺ ions in А²В⁶ semiconductors are presented in this paper. 

Results of further investigation into original concept of charge pumps in the structure of photoelectric cells show that charge pumps are formed due to the formation of spatial defect−dopant complexes which produce a qualitative change in the transport mechanism of light generated charges at the base of the solar cell. For the first time a large scale charge pump manufacturing process has been offered. This process involves a non−thermal or «cold» photon annealing and uses standard photon annealing equipment. The photon annealing effect is achieved by using an original photomask (removable). The mask provides an annealing pattern with multiple light sources and heat insulation of the target wafer. This process is called local photon annealing (LPA). Due to its efficiency and simplicity the process does not require significant industrial investment. Experimental results show that it is possible to increase short circuit current and maximum power output of a solar cell with the use of the LPA technique. Experimental solar cell samples have been chosen from different manufacturers. 

This work is an experimental justification of the choice of temperature and time modes designed for the heat treatment of real magnetrons, the end result of which is the initial decomposition of barium carbonate to barium oxide. We have experimentally determined the temperatures of polymorphic transitions in barium carbonate and the temperature of barium carbonate dissociation in different atmospheres, i.e. air, argon, carbon dioxide and in vacuum, for physical modeling of processes occurring in pumped magnetrons. We have determined the phase composition of the test barium carbonate specimen at room temperature by X−ray phase analysis (XPA) on a diffractometer before and after heating and experimentally investigated the effect of temperature and time of isothermal exposure on the phase composition on a high temperature diffractometer. We have studies the chemical and physicochemical processes occurring in the samples during heating using a derivatograph. We have calculated the enthalpy of the polymorphic transitions and the activation energy of dissociation. We have presented quantitative data characterizing the kinetics of phase transitions for various heat treatment modes and demonstrated the temperature existence ranges of different phases. We have established that reducing the heating rate and increasing the time of heating interruptions slow down the process of BaCO3 to BaO transition. We have established that sintering of the powder occurs during heating of barium carbonate. 

The degradation of CMOS operational amplifiers with bipolar and CMOS input stages under irradiation at different dose rates and temperatures has been investigated. We show that such circuits can be susceptible to enhanced low dose rate and temporal degradation. Moreover, some features inherent to radiation response of bipolar devices have been revealed in operational amplifiers which contained CMOS elements only, for example, an increase in degradation with the temperature applied during irradiation. This is not typical for most CMOS devices. Our results suggest that the test procedures for devices and integrated circuits containing bipolar and CMOS elements should combine existing test approaches developed for the radiation testing of bipolar and CMOS devices. We have also shown that ionizing current generated by irradiation can affect the input current of operational amplifiers with CMOS input stages as measured during testing. This current can be estimated as the difference between input currents measured during irradiation and immediately after an interruption of irradiation.