The head of the laboratory is Ramizulla Abdullaevich Muminov, Academician of the Academy of Sciences of the Republic of Uzbekistan, corresponding member of the Russian Academy of Technological Sciences, doctor of physical and mathematical sciences, professor. Twice winner of the State Prize of the Republic of Uzbekistan in the field of science and technology.

The laboratory was organized in 1971, in the Physico-Technical Institute of the Academy of Sciences of Uzbekistan.

In the group of Muminova R.A., at present - one academic, one Ph.D., as well as scientific employees (9) and engineering staff (6) are working in the laboratory team: 9 + 6 people in total.

Fundamental studies of physical processes in p-i-n structures, which are the main elements of semiconductor electronics, both in the regime of strong charge, pooling of the base (i) region and under conditions of double injection, when a plasma of high concentration fills (i) - the region had important scientific and practical significance. These studies essentially opened on the one hand a new scientific direction - the study of hydrodynamic phenomena in a degenerate electron-hole plasma and allowed to solve the problem of creating highly-point semiconductor lasers in the infrared range of radiation with a large volume of the active region and, on the other hand, representation in the field of physics and technology of semiconductor detectors of nuclear radiation. The basis of this representation is the experimentally established concept of an essential role in the formation of the properties of the combined region and the functional characteristics of the fluctuation detectors in the distribution of defects in the crystal lattice, leading to the appearance of local inhomogeneities in the distribution of the electric field in the volume of the crystal.

The development of this direction allowed in the future to establish the physical nature and properties of local inhomogeneities, stimulated the creation of diagnostic methods for the selection and control of the source material. The group for the first time proposed and implemented a comprehensive study of the response of semiconductor materials and devices (detectors, solar cells, surface-barrier and MIS-structures) to external influences: light, non-uniform strong pulsed magnetic field, ultrasonic fields. The result of studies of phenomena, arising in semiconductors under these conditions, was the development of fundamentally new methods for carrying out a low-temperature diffusion and annealing process, methods for eliminating defects in semiconductors, and accelerating the processes of ion diffusion; ways to improve the spectrometric characteristics of detectors and the energy characteristics of solar cells. A physically important aspect of the developed direction is the theory of the flow of kinetic phenomena in semiconductors under conditions of acoustostimulated nonuniformity of thermal phonons. It allows deeper and broader understanding of the mechanisms for the formation of functional characteristics of semiconductor devices in ultrasonic fields and the specificity of the interaction of ultrasonic waves with lattice defects, to carry out targeted changes in the defect structure of semiconductor materials, and also opens the prospects for creating highly sensitive instruments with the use of acousto-effects. As a result, the group solved the task of creating, on the basis of domestic industrial, silicon semiconductor detectors of nuclear radiation for various purposes with operational characteristics at the level of world standards. They are detectors with an extended sensitive area from 5 μm to hundreds of microns, and from 1 mm to 10 mm, and also show ways of obtaining detectors by a sensitive area of ​​tens of mm on a physical basis of the exclusion phenomenon in semiconductor structures. Based on the results of this research, the NPO "Physics - Sun" of the Academy of Sciences of Uzbekistan has established a small series of semiconductor nuclear radiation detectors for various purposes. According to the conclusion of experts, they have characteristics at the level of world standards and are widely used in studies on board of space vehicles, in the Takomak and Dolphin type installations, at the accelerators in Serpukhov, Dubna, Alma-Ata, and also in a number of other scientific experiments, special equipment. The developed detectors were repeatedly awarded with gold, silver and bronze medals at various exhibitions.

In the past 15-20 years, the main areas of research work of the group are Muminov R.A. are:

two areas of science and technology:

1) Development and manufacturing of highly effective silicon-p-i-n lithium detectors of large volumes of sensitive area, and also a sensitive surface. They can find application in science and technology, geology, environmental protection, medicine, etc.

2) Scientific, technical and technological research and development of new physical ways to improve the efficiency of silicon solar cells.

Using the achievement of nanophysics, (nanotechnology, holography, superlattices, etc.).

The main scientific, technical and technological results and achievements in the field of the first area of ​​research:

In chronological order, bring all the most important scientific results (since the beginning of the 90s on the detector topic). 

The main scientific, technical and technological results and achievements in the field of the second area of ​​research:

Such in chronological order to bring important results from the reports on the subject of SE.

Publications on SEs are mainly in English.

Main results and today's topics:

The objects of investigation are both single-crystal semiconductors-silicon and gallium arsenide, and polycrystalline films of the cadmium and bismuth telluride type, as well as oxide layers in the intergranular regions and on the surface of structural metals, such as alumina (Al2-xO3 + x) and titanium oxide.

The main attention is paid to the structural features of semiconductors on which the operational properties of the sensors, based on them, depend, in particular, the sensors of accumulated fatigue damage, as well as the sensors of ionizing radiation and optical quantities.

In particular, it was found, that the electrical structure of silicon, which has a resistivity in the region of 1 - 3 Com cm, makes it possible to fabricate silicon-lithium ionizing radiation detectors, that are not inferior in their properties to the corresponding Si (Li) detectors, made from an expensive unalloyed silicon.

It is also established, that when an ultrasonic wave is applied to a semiconductor or structure of semiconductor, the structure of the lattice and the nature of its interaction with the electronic subsystem change, which for the frequencies and amplitudes found and for certain exposure durations, leads to an improvement in the adhesion properties of the contacts and the operational properties of semiconductor solar cells [3 -5].

Employees of the laboratory improved the technology of obtaining semiconductor epitaxial layers, based on gallium arsenide and its compounds. Field effect transistors, based on thermoelectric and photovoltaic effects, two-barrier and multilayer structures with an integrated hetero and metal-semiconductor region on a spectral range of 0.4-1.6 μm with a high coefficient of internal amplification and parameters, exceeding the known analogs, are developed. Technological methods of creating photoelectric devices with a moth-eye interface, that are resistant to radiation and temperature influences, are developed.

A fundamentally new approach is the development of sensors for accumulated fatigue damage of structural materials. Here the main problem is the structural stability of the material. In the process of fatigue evolution, we can not consider as a given set of interacting units, or a certain set of transformations of these units. This means, that the definition of the system must be modified in the course of evolution. This kind of evolution is associated with the notion of structural stability. We are talking about the reaction of a given system to the introduction of new units, that are able to multiply and involve various processes, occurring in the system.

The problem of stability of a system, with respect to changes of this type, reduces to the following. Introduced in a small amount in the system, new components lead to the emergence of a new network of reactions between its components. A new network of reactions begins to compete with the old way of functioning of the system. If the system is structurally stable with respect to the invasion of new units, a new mode of operation is not established, and the new units themselves die. But if structural fluctuations successfully "take root" (for example, if new units multiply quickly enough and manage to "grab" the system before they die), then the entire system is rebuilt to a new mode of functioning: its activity is subject to a new "syntax".

Important in the evolutionary theory of fatigue is the resulting feedback between macroscopic structures and microscopic events: macroscopic structures, arising from microscopic events, should in turn lead to a change in microscopic mechanisms. Such interrelated processes generate very complex situations, and this circumstance must be recognized when starting to model them.

Group of Academician Muminova R.A.
The main research areas of Professor Muminova's group are:
The fundamental foundations of creating instrumental semiconductor structures with various functional purposes, being the main direction of the research of the group, are academician Muminova R.A. is aimed at solving the following problems in the physics of semiconductor devices:

 A model is developed and a complete theory of a new contact structure is presented, which has needle-like geometry and functionally performs the role of the pn junction (that is, the theory of the nano-sized "pn junction" is developed).
   A GaAs / AlGaAs heterophore-converter, based on a GaP substrate with a high thermal conductivity, was developed. This heterophoto converter is able to operate in the range of solar radiation concentration Kc = 1 ... 100 in the passive heat sink mode.
   A technology is proposed for the formation of nanoinclusions, based on silicon atoms on the surface of silicon single-crystal plates. This structure has a wider spectral sensitivity relative to the traditional flint photoconverters.
   A theoretical model has been developed, that describes the formation of a space-charge region in fundamentally new contact structures, consisting of a semiconductor base and inclusions on its surface. It is shown, that the specificity of a new type of contact is completely determined by the electrical capacitance on the connections. The properties of a new type of contact are distinguished, both in structure and in extent, from similar contact properties characteristic of Schottky barriers, continuous p-n junctions, and heterojunctions.
    The physical optimal conditions for the formation of a diffractive concentrator in the form of relief diffraction gratings are determined. The features of their use, as concentrating systems in solar cells, based on arsenide-gallium heterostructures are studied. It is shown, that the use of diffraction and holographic concentrators is quite effective and they do not require an automatic tracking system for the Sun. All this creates new approaches for the wide application of arsenide-gallium solar cells.
    A theory is constructed and a mechanism is established for the formation of a space-charge region in fundamentally new contact structures, consisting of a semiconductor base and inclusions on its surface.
   A theoretical model for the formation of a space-charge region in fundamentally new contact structures, consisting of a semiconductor base and nanoinclusions, applied to it, has been developed.
    The differences in the properties of a new type of contact, both in structure and in extent with respect to analogous contact phenomena characteristic of Schottky barriers, continuous p-n junctions and heterojunctions, are determined.
   A theoretical model of a new contact structure, providing effective phototransformation in a wide infrared range of solar radiation, has been developed. It is shown, that the effective absorption of infrared radiation becomes possible, due to the elongation of the space charge region, which is provided by the creation of many nanoscale p-n junctions directly on the substrate.
Methods for the formation of nanocrystalline inclusions of silicon (nc-Si) in the dielectric matrix of silicon oxide SiO2 are studied. A method for creating nc-Si on a silicon surface was chosen to improve the efficiency of silicon solar cells.
   Mechanisms for the formation of pore etching on the surface of a silicon wafer, methods and etching regimes with the aim of creating a given pore concentration and topology for further doping of the developed silicon surface, ie creation of a pn junction, were studied.
   The possibility of formation of nc-Si p-p SiO2 on the developed silicon surface by the diffusion method from parallel sources was investigated. The effects of the distribution and the concentration of impurities on the electrical properties of the pn junction are studied and the possibility of controlling optical and electrical parameters, depending on the conditions of heat treatment, is shown.
   Computer simulation has been used to study the optical and electrical properties of the nc-Si-SiO2 system. It has been established, that the effective optical constants of porous silicon depend strongly on the concentration and topology of the pores. This dependence makes it possible to create effective antireflection coatings for solar photocells.
   Nanostructural processing of the surface of a semiconductor and the application of zero-dimensional nanoclustering on it from another homogeneous semiconductor material leads to the appearance of quantum dots (CT), that is, nanocrystals with dimensions of 10-40 nm. These nanowires are identified as quantum dots, since their energy spectrum consists of a set of discrete levels similar to that of a single atom. Quantum points of high concentration on the sensitive surface of the FP contribute to the emergence of an additional concentration of e-pairs in the processes of converting solar radiation into electrical energy.
   The analysis of scientific publications on the current state of the problem of increasing the efficiency of conversion of solar and thermal energy into electrical energy by means of solar cells and thermoelectric converters is carried out.
    To conduct further research in the field of increasing the efficiency of converting the energy of solar radiation into electrical and thermal energy, taking into account the wide application of photo- and thermoelectric converters in photovoltaics, as well as the availability of manufacturing technology, silicon solar cells and thermoelectric converters, based on the bismuth- tellurium.
    A design of a combined unit for the conversion of solar radiation, consisting of solar cells and thermoelements, is proposed. The results of measurements of the parameters of a combined installation, based on photocells from crystalline silicon and thermoelements of the bismuth-tellurium system are given. It is shown, that the combined unit increases the efficiency of conversion of solar radiation by 5% and such installations can be operated in countries with a very hot climate.

 A laboratory sample, a combined photoconverter-thermoelectric converter, based on silicon cells and bismuth-tellurium thermocouples, was developed and manufactured. The possibility of increasing the efficiency of the combined system by 5%, compared to a photovoltaic battery, is shown.
Applied fundamentals of creating instrumental semiconductor structures with various functional purposes, being the main direction of research of the group of Academician Muminova R.A., is aimed at solving the following problems in the physics of semiconductor devices:

As a result of research and technological work, we developed a method for manufacturing semiconductor coordinate-sensitive detectors of large sizes (D ~ 100 ÷ 120 mm and W> 1.5 mm), based on Si (Li) p-i-n structures with 8, 16 and 32 bands. A laboratory model of a universal low-background installation, based on Si (Li) detectors of large volumes (S = 50 cm2, Wi≥2 mm), was developed, manufactured and presented. The laboratory radiometer is designed and manufactured to measure volumetric activity (OA) of radon-222 and the number of decays of 216Po (ThA) in the air of residential and working premises, as well as in the open air. The multifunction thermoelectric generator (MTEG) is designed for direct conversion of thermal energy (wood-burning stove, steam energy, gas and diesel fuels, heat, generated by various operating equipment, and solar energy) into electrical energy and provides continuous 24-hour operation, without constant monitoring of its operation. MEGEG is designed to provide continuous power supply to the heating system (automatic, circulation pumps, etc.), as well as for emergency lighting, charging of batteries (automobile, mobile phone, video camera, laptop, etc.) power supply of the security and fire alarm system, TV, computer, audio equipment and so on. Multichannel thermal recording device (MTRU) is designed for long-term measurement in eight points of space with subsequent recording and storage of measurement results on a computer and MMC card. MTRU is designed for operation in production and in laboratories, where control, registration, and automatic thermostating are necessary.