Prehistory of Volgograd State University. 1971–1980

Introduction. The authors analyze the process of establishing a state university in Volgograd, the last university set up in the RSFSR during the existence of the USSR. Materials. This study is based on the basis of archival materials first introduced into scientific use (State Archive of the Russian Federation (SARF), Russian State Archive of Recent History (RSARH), Center of Recent History Documentation of Volgograd Region (CRHDVO)). Analysis and Results. The initial idea of the representatives of governing bodies in Volgograd region to organize a university on the basis of Volgograd Polytechnic Institute did not find support from the leadership of the country in 1971. In 1972 it was decided to start organizing a new type of higher education institution for Volgograd, that is a classic university. This idea found support in Moscow, which was manifested in the resolutions of the Secretariat of the CPSU Central Committee in 1973 and the USSR Council of Ministers and the RSFSR Council of Ministers in 1974. The necessity for creating appropriate educational and teaching resources and facilities, the manpower problem and insufficient funds led to postponing initially proposed dates for the University opening from 1974 to 1978, and then to 1980. The first admission of students in 1980 was in the building of a comprehensive school specially built for this purpose near the future University complex, the first building of which would be put into service only in 1983. The issue of the development of the young University was under the constant control of the Council of Ministers of the RSFSR for many years. Only in March 1986 it was decided to discontinue supervision over the resolution of the Council of Ministers of the RSFSR no. 561 of October 21, 1974

Admittance of MIS structures based on graded-gap MBE HgCdTe with Al2O3 insulator

The paper presents the results of studies of the admittance of MIS structures based on heteroepitaxial MBE n (p)-Hg0.78Cd0.22Te with insulator coating SiO2/Si3N4 and Al2O3 in the test signal frequency range 10 kHz-1 MHz at temperatures ranging from 8 to 220 K. The main parameters of MIS structures with different insulators were determined. MIS structures with Al2O3 have a large enough insulator capacitance (compared to SiO2/Si3N4), a significant modulation capacitance on the CV characteristics, high dielectric strength and low values of the flat-band voltage. The effective charge density found from the value of the flat-band voltage and slow interface trap density for structures with Al2O3 comparable with the corresponding densities for structures with SiO2/Si3N4

Impact of the graded-gap layer on the admittance of MIS structures based on MBE-grown n-Hg1-xCdxTe (x = 0.22-0.23) with the Al2O3 insulator

The impact of the presence of the near-surface graded-gap layers with an increased content of CdTe on the admittance of MIS structures based on MBE-grown n-Hg1–xCdxTe (x = 0.22–0.23) with the Al2O3 insulating coating has been experimentally studied. It has been shown that the structures with a gradedgap layer are characterized by a deeper and wider capacitance dip in the low-frequency capacitance–voltage (CV) characteristic and by higher values of the differential resistance of the space-charge region than the structures without such a layer. It has been found that the main features of the hysteresis of capacitance dependences typical of the graded-gap structures with SiO2/Si3N4 are also characteristic of the MIS structures with the Al2O3 insulator. The factors that cause an increase in the CV characteristic hysteresis upon formation of the graded-gap layer in structures with SiO2/Si3N4 or Al2O3 are still debatable, although it may be assumed that oxygen plays a certain role in formation of this hysteresis

Modern Trends of the Development of Primary School-Aged Children (Literature Review)

The beginning of children’s school education is a potential risk of morphofunctional and psycho-physiological disorders in the body because of the significant reduction in daily physical activity, the change in day regimen, emotional and intellectual stress, which are often inadequate for the age-related psycho-physiological capabilities of schoolchildren. In this paper, we analyzed the literature on the development of modern children of primary school age according to the results of the assessment of morphological, functional and mental indicators. The identification of a general trend in the development of primary school-aged children is necessary for determination and development of health-saving programs to implement in the system of modern education. A review of data on the development of younger school children over the past 20 years shows an increase in the number of children with digressions in physical development, deterioration in physical fitness, delay of biological age from actual age, stress of the cardiovascular system, decrease in lung capacity and muscle strength. This pattern is manifested regardless of the region of residence and the nationality of children. There is an increase in the number of children with learning difficulties. Among the reasons for these changes, researchers highlight the complexity of the educational program, physical inactivity, the delay of physical development and, at the same time, medical and social successes of the state, allowing preserving the life of newborns even with somatic and neurological abnormalities. In connection with the identified trend of development of modern primary school children, the measures are needed to optimize children’s learning activities by the following criteria: level of physical activity, intensity of intellectual loads, rest mode

Unipolar barrier structures based on HgCdTe for infrared detection

One of the topical areas of solid state photoelectronics is the creation of infrared detectors based on unipolar barrier systems (for example, with an nBn architecture). The greatest progress has been achieved in the development of barrier detectors based on semiconductors of the AIIIBV group, which is associated with the possibility of realizing systems with a zero barrier in the valence band. Unipolar barrier detectors based on mercury cadmium telluride (HgCdTe) grown by molecular beam epitaxy (MBE) are of interest due to significant technological advantages, since the creation of such devices can abandon the defect forming procedure of ion implantation. Despite a significant number of theoretical works, only a few attempts are known to practically implement nBn detectors based on MBE HgCdTe

An experimental study of the dynamic resistance in surface leakage limited nBn structures based on HgCdTe grown by molecular beam epitaxy

Mid-wave infrared nBn structures based on HgCdTe grown by molecular beam epitaxy on GaAs (013) substrates were fabricated. The composition in the absorbing layer was 0.29, and in the barrier layer it was 0.67. It was shown that the dark currents of the created nBn structures are limited by the surface leakage component. To study the bulk component of the dark current, it was proposed to use the admittance measurements of test metal-insulator-semiconductor (MIS) devices based on fabricated nBn structures in the case of the formation of a backward contact to the absorbing layer. It was established that surface leakage does not afect the dynamic resistance of the MIS device barrier. The dependence of the dynamic resistance of the barrier layer (Rb) of the MIS device in the accumulation mode on the area of the front electrode (A), voltage, and temperature was determined. It was shown that, with the exclusion of surface leakage, the values of the RbA product in a temperature range of 230–300 K at forward biases are determined by the difusion current of holes from the contact layer, and at reverse biases, by the difusion current from the absorbing layer. It was found that at temperatures of 210–300 K, RbA values exceeding the values of this parameter determined according to the empirical model Rule 07 were realized in the fabricated structures

Electrical properties of optimized nBn structures based on HgCdTe grown by molecular beam epitaxy

The use of unipolar barrier architectures in infrared detectors based on HgCdTe grown by molecular beam epitaxy (MBE) provides significant technological advantages. Earlier, the authors of the manuscript presented the results of a study of dark currents [1] and admittance [2] of the first variants of MBE HgCdTe nBn structures. This paper presents the results of electrical characterization of nBn structures with parameters optimized for detection in the spectral ranges 3–5 (MWIR) and 8–12 (LWIR) µm

Influence of As+ Ion implantation on properties of MBE HgCdTe near-surface layer characterized by metal–insulator–semiconductor techniques

The effect of As+ ion implantation on the electrical properties of the near-surface layer of n-HgCdTe films grown by molecular beam epitaxy (MBE) on Si (310) substrates was experimentally studied. A specific feature of MBE n-Hg0.78Cd0.22Te films is the presence of near-surface graded-gap layers with a high CdTe content, formed during epitaxial growth. The properties of as-grown films and films after As+ ion implantation with ion energy of 200 keV and fluence of 1014 cm−2 were studied. Post-implantation activation annealing was not performed. Test metal–insulator–semiconductor (MIS) structures were created based on as-grown and as-implanted samples by plasma-enhanced atomic layer deposition of Al2O3 insulator films. The admittance of the fabricated MIS structures was measured over a wide range of frequencies and temperatures. When determining the parameters of MIS structures, we used techniques that take into account the presence of near-surface graded-gap layers and series resistance of the HgCdTe film bulk, as well as the high density of slow surface states. It was found that, in as-implanted samples, the donor center concentration in the near-surface layer exceeds 1017 cm−3 and increases with distance from the HgCdTe-Al2O3 interface (at least up to 90 nm). After implantation, the conductivity of MBE HgCdTe film bulk increases markedly. It was shown that, for as-implanted samples, the generation rate of minority charge carriers in the MBE HgCdTe surface layer is significantly reduced, which indicates the appearance of a low defect layer with a thickness of at least 90 nm

Detection of Pionium with DIRAC

The aim of the DIRAC experiment at CERN is to provide an accurate determination of S-wave pion-pion scattering lengths from the measurement of the lifetime of the pi+ pi- atom. The measurement will be done with precision comparable to the level of accuracy of theoretical predictions, formulated in the context of Chiral Perturbation Theory. Therefore, the understanding of chiral symmetry breaking of QCD will be submitted to a stringent test