To implement the technology of thermally stimulated diagnostics of anisotropy and optical axes of crystals, the sample is thermostated at a temperature not exceeding the melting point, an electric field not exceeding the breakdown field is applied to the sample, polarization is produced for a time greater than the relaxation time at this temperature. After that, without disconnecting the electric field, cooling to the temperature of liquid nitrogen is performed, then the field is switched off, the sample is linearly heated to a temperature above the polarization temperature and the obtained thermally stimulated depolarization (TSD) spectra taken along and perpendicular to the optical axis of the sixth order C6 crystal are examined. When comparing the obtained spectra, the presence of anisotropy is determined, and the exact direction of the optical axes is determined by the magnitude and presence of the TSD maxima.

The article is devoted to the issues of numerical simulation of field Hall sensors based on the "silicon on insulator" structure with two control gates. To solve the problem, a two-level local-one-dimensional computational model is used. At the first level, a series of one-dimensional Schrödinger—Poisson equations are solved, which describe the distribution of the electron density across the heterostructure in different sections. The obtained information is transmitted to the second level, where the current characteristics of the element are calculated. The numerical simulation results are compared with the experimental data obtained for field Hall sensors. Comparative analysis shows good agreement between calculated and experimental data. The developed computer model makes it possible to carry out a multivariate analysis of various heterostructures, which creates the basis for optimizing devices of the class under consideration.

Five samples of colloidal dispersions of gold nanorods with various aspect ratio were studied using methods based on light scattering. Transmission electron microscopy was used as a reference method. The advantages and disadvantages of the dynamic light scattering and nanoparticle tracking analysis methods for determination of the geometric parameters of nanoparticles, their concentration, monodispersity, as well as for detection of large aggregates and quasispherical impurities were given. It was shown that the method of depolarized dynamic light scattering can be used for determination of the geometric parameters of liquid dispersions of colloidal gold nanorods. Moreover, it was found that the presence of large impurities or particle aggregates in the sample strongly affects the measurement results. The presence of large particles in the dispersion can be determined using dynamic light scattering or nanoparticle tracking analysis methods. The method of dynamic light scattering was also found to be more sensitive to the presence of even a small amount of large impurities or aggregates in the sample. The monodispersity of a liquid dispersion of nanorods can also be estimated by dynamic light scattering and nanoparticle tracking analysis methods, and, comparing to electron microscopy, the measurement results can be considered more statistically reliable due to the analysis of a larger number of particles. It was found that the increase of spherical particles concentration in the composite dispersion of nanospheres and nanorods leads to a decrease in the contribution of the rotational mode in the total scattering intensity. In addition, the concentration of quasispherical impurities in samples of liquid dispersions of colloidal gold nanorods was calculated based on measurements of the depolarization degree of scattered light.

In present study is considered the influence of the regimes of passivating dielectric silicon nitride SiN_x films deposition by the chemical vapor deposition in an inductively coupled plasma (ICP CVD) on the parameters of the high electron mobility transistors (HEMT) based on AlGaN/GaN heterostructures. By the investigation of dielectric material layers’ parameters was revealed the influence of RF and ICP generators power, working gases flows ratio on the films growth rate and perfection, also their effect on the CVC of passivated HEMT. With RF power increasing the deposition rate did not change, while its growth was observed with ICP power increasing. The transistor slope strongly decreases with RF power increasing, its maximum was achieved with a minimum RF power of 1 W. At the initial moment of deposition even at low values of RF power (at 3 W already) the transistor structure becomes completely inoperative. Shown, that the deposition process of dielectrics for the HEMT passivation must begin at the lowest possible RF power. An AlGaN/GaN UHF HEMT structure passivation process has been developed, allowing the deposition of conformal films and obtaining low drain-source currents in turn-off transistors without deterioration in the open state — at no more than 15 and 100 μA for 1,25 and 5 mm Т-gate width respectively (U_G = –8 V and U_SD = 50 V).

The problems of increasing the reliability of microelectromechanical systems are considered on the example of an automobile voltage regulator. A model of the process is proposed and a study of the effect of temperature on the formation of stress fields in semiconductor structures of active elements of the controller is carried out. The studies assumed of a possible reason for the change in the parameters of the regulator due to the appearance of defects in the crystal structure of the semiconductor material in the structures of integrated voltage regulators. For the study, a mathematical model was proposed that describes the behavior of a semiconductor element of a real car voltage regulator. It was found that the distribution of stresses in the structures is uneven and the maximum value of stresses reaches the edges., An increase in temperature gradients in the structures of regulators leads to the formation of dislocations that change the electrical characteristics of devices. As a result of modeling, it has been established that thermoelastic stresses arising in the process of manufacturing and functioning of semiconductor structures of a regulator in regulators of this type can cause a change in the structure of a semiconductor device due to relaxation of elastic stresses at dislocations. in cars. Measures are proposed, including thermostating of the sensitive elements of microelectromechanical structures, which will increase their service life.

A model is proposed for describing the self-organization of localized charges and quantum scattering in undoped GaAs/AlGaAs structures in which a two-dimensional gas of electrons or holes is created by the corresponding gate voltage. We assume that in such a metal-dielectric-undoped semiconductor structure carrier scattering on surface charges localized at the interface between GaAs and the dielectric dominates. Proposed model considers these charges and the corresponding image charges in the metal gate as a closed system in a thermostat. The electrostatic self-organization for this system in thermodynamic equilibrium is studied numerically using the Metropolis algorithm in a wide temperature range. It is shown that, at T > 100 K, a simple formula derived from the theory of two-dimensional one-component plasma gives almost the same behavior of the structural factor at low wave numbers as the Monte Carlo calculation. The scattering times of gate-induced carriers are described by formulas in which the structural factor characterizes the frozen disorder in the given system. In these formulas, the behavior of the structural factor at small wave numbers is decisive. A calculation using these formulas with disorder corresponding to infinite T gives two to three times shorter scattering times than in the corresponding experiments. We found that the theory is consistent with experiment at a freezing point of disorder T ≈ 1000 K for a sample with a two-dimensional electron gas and T ≈ 700 K for a sample with a two-dimensional hole gas. The found values are an upper estimate of the freezing temperature in the studied structures, since the model ignores sources of disorder other than temperature.

The effect of impurities on the electrical resistance of aluminum is well understood. It is known that the conductivity of aluminum is 65.45 % of the conductivity of copper. The tensile strength of aluminum wires is 150—170 MPa, which, with equal conductivity, is about 65 % of the strength of a copper wire. Such strength of aluminum wires is sufficient to support its own weight and may be insufficient when overloaded with snow, ice or wind.

One of the ways to increase the strength of aluminum wires is the use of aluminum alloys having increased strength with a sufficiently high conductivity. One representative of the group of such alloys is the alloy E-AlMgSi (Aldrey). The main hardener of this alloy is the Mg₂Si phase, which gives aluminum high mechanical properties.

The paper presents the results of a study of the kinetics of high-temperature oxidation and electrochemical corrosion of indium-doped aluminum conductor alloy E-AlMgSi (Aldrey). Using thermogravimetry, it was shown that indium additives and temperature increase the oxidizability of the E-AlMgSi alloy (Aldrey). In this case, the apparent activation energy of the oxidation of alloys decreases from 120.5 to 91.8 kJ/mol. The oxidation rate of alloys determined by the potentiostatic method in a NaCl electrolyte showed that the corrosion resistance of alloys with indium is 20—30 % higher than that of the original alloy. With increasing concentration of NaCl electrolyte in the electrochemical potentials of the alloys decrease, the corrosion rate increases regardless of their composition.