HgCdTe remains to be the most important material for infrared photodetectors despite numerous attempts to replace it with alternative materials. It is interesting, however, that none of these competitors can compete in terms of fundamental properties. In addition, HgCdTe exhibits nearly constant lattice parameter that is of extreme importance for new devices based on complex heterostructures. The development of sophisticated controllable vapor phase epitaxial growth methods, such as MBE and MOCVD, has allowed fabrication almost ideally designed heterojunction photodiodes. In the paper examples of novel devices based on heterostructures operating in long wavelength, middle wavelength and short wavelength spectral ranges are presented. Recently, more interest has been focused on p-on-n junctions heterostructures. As the infrared technology continues to advance, there is a growing demand for multispectral detectors for advanced IR systems with better target discrimination and identification. HgCdTe heterojunction detectors offer wavelength flexibility from medium wavelength to very long wavelength and multicolor capability in these regions. The main challenges facing all multicolor devices are more complicated device structures, thicker and multilayer material growth, and more difficult device fabrication, especially when the array size gets larger and pixel size gets smaller.

A technology was designed and the photodetector modules were manufactured for the 3 - 5 and 8 - 12 micrometer spectral range based on the Hg_1-xCd_xTe/GaAs heterostructures and GaAs/AlGaAs multiquantum well structures grown by the molecular beam epitaxy method. The photosensitive HgCdTe layers were grown on the GaAs substrates with the intermediate buffer layer of CdZnTe. To decrease the surface influence on the recombination processes graded gap HgCdTe layers with the increased to the surface composition were grown. A silicon multiplexer was designed and manufactured on the CMOS/CCD technology with frame rate 50 Hz. Hybrid assembly of the photodetectors array and the multiplexer was produced by the group cold welding on the indium bumps with control of the connection process. The manufactured 128 X 128 FPAs on the HgCdTe with the cut-off wavelength 6 micrometer and 8.7 micrometer had the NEDT value 0.02 K and 0.032 K, correspondingly, at operating temperature 78 K and frame rate 50 Hz. The photosensitive GaAs/AlGaAs multiquantum well structures were manufactured by the MBE method. It is shown that the designed technology allows to produce 128 X 128 photodetector arrays ((lambda) _max equals 8 micrometer) with the NEDT value 0.021 K and 0.06 K at operating temperature 54 K and 65 K, correspondingly.

Infrared detector arrays can be divided in two distinct classes: hybrid (and typically photon) detectors and monolithic (and generally thermal) detectors. Hybrid detectors involve flip-chip integration of the detector array and the readout chip, require cooling and thus cause substantial system cost. Monolithic detectors do not suffer this system overhead and most notably the microbolometer thermal detectors allow ambient operating temperature. IMEC focuses on III-V (InGaAs, InAs and InAsSb) short-wave and mid-infrared detector arrays for hybrid integration on one side and surface micromachined uncooled polySiGe microbolometer arrays on the other hand. Progress in both types of detector systems is reported.

The abnormal photoelectric properties of MIS structures, such as a significant photo-emf signal in the state of enhancement and a drop of the local photo-emf in inversion, were investigated with integrated and local photoelectric measurements. It has been established that the reason for the significant photo-emf signal in enhancement and the related features of the photoelectric properties of the structure is the photosensitivity in the region away from the electrode associated with a nonuniform distribution of electrically active defects. It has been demonstrated that the nonuniformity in surface potential (between the subelectrode region and the region away from the electrode (after-electrode region) or between different points in subelectrode region) may result in a drop of the local photo-emf in inversion. A conclusion has been made that the redistribution of nonequilibrium carriers along the boundary must be taken into account in constructing equivalent circuits of actual MIS structures.

We present results of the studies of photoconductivity and transient processes in n-PbTe(Ga) epitaxial films of thickness approximately 0.2 micrometer prepared by the hot wall technique on BaF (formula available in paper) substrates. The photoelectric properties are investigated in the temperature range 4.2 - 300 K under infrared (IR) illumination by GaAs light-emitting diode with (lambda) equals 1 micrometer and by a white light lamp. The low-temperature measurements reveal the IR-photoconductivity threshold at T_C approximately equals 150 K (for the flux density (formula available in paper), that exceeds by 40 K and 70 K the temperatures relevant to more thick films (approximately 2 micrometer) and to single crystals, respectively. This substantial increase of T_C in thin films gives us an opportunity to estimate the recombination barrier of Ga impurity in PbTe.

Illumination of a double (formula available in paper) As heterostructure by a red light emitting diode results in a negative photoconductivity that, after the diode is switched off, slowly relaxes to a positive persistent photoconductivity, characterized by about 1.5 increase of a two-dimensional hole concentration. This metastable state may be explained in a frame work of the model in which deep electron traps are supposed to be located above the Fermi level on the inverted heterointerface.

Two X sixty-four linear photodiode arrays on the base of HgCdTe MBE grown layers with CCD silicon readouts were designed, fabricated and tested. It is shown that detectivity for the given arrays even with skimming mode used for long integration times that is need for large square n-p-junctions used and cut-off wavelength of 12.2 micrometer was near the ultimate performance limit.

The theoretical and experimental investigations of the main zone parameters of the quaternary solid solutions CdMnHgTe and MnHgTe are represented in the given paper. As a result of these investigations the empirical formulae for the energy gap width and intrinsic carrier concentration in the wide range of the temperature and compositions are proposed. The results of the theoretical calculations agree well with the experimental data. On the base of these empirical expressions the calculation of the Schottky diode main parameters have been carried out. The Schottky barrier height calculation procedure was examined. This procedure take into account the influence of surface states and intermediate dielectric layer. The theoretical calculation results are compated with experimental data.

Band structure of [100] (CdTe)_m/(Cd_1-xMn_xTe)_n superlattices is calculated theoretically in dependence of semiconductor CdTe and Cd_1-xMn_xTe layers width and magnetic component concentration. Calculations are carried out within semiempirical tight-binding method, which includes s-, p-orbitals of each atom and cation d-orbitals. Mn 3d-states contribution to the formation of the superlattice energy spectrum is analyzed. It is shown that a superlattice on the base of diluted magnetic semiconductor Cd_1-xMn_xTe with small width of CdTe layers is a semiconductor materials with the similar magnetic properties but with more complicated dependence of crystal forbidden band gap on magnetic component concentration.

It was investigated photosensitivity of double heterostructures. Such double heterostructures were created by pressing and forming optical contact porSi/Si heterostructures and GaSe (d approximately 20 micrometer) thin single crystal substrate. An experimental investigation of GaSe/porSi/Si double heterostructures was connected with current-voltage and photovoltaic effects. It was observed wide band photovoltaic sensitivity from 0.4 to 1.2 micrometer for different heterostructures. Using energy band configuration it was explained obtained curves. GaSe/porSi/Si heterostructure were also high sensitive to mechanical stresses. It was concluded that heterojunction on the basis GaSe/porSi/Si plates may find application as wide-band photoconverters and tensosensitivity devices.

The paper theoretically examines the peculiarities of photoconductivity of thin graded-band-gap layers with linear profile of energy gap and Ohmic contacts. It is analyzed in detail the cases of illumination of the layers from wide gap side by polychromatic light with spatially constant carrier photogeneration function and by strongly absorbed monochromatic light. Carrier extraction effect is shown to cause strong nonmonotonous field dependence of effective lifetime in the case of thin layers. The maximum of carrier effective lifetime is reached when the total force acting on photocarriers is equal (in the case of bulk photoexcitation) or close (in the case of local photogeneration function) to zero. Such a field dependence of effective lifetime can lead to formation of negative differential photoconductivity of N- type. The photo-current peak occurs at the external field strength approximately equals to that of quasielectric field in the case of layer thickness comparable with the minority carrier length and at the substantially stronger fields in the case of very thin films.

The effect of mechanical strain on degradation processes in GaAs-AlGaAs laser heterostructures (LHS) with stripe geometry and in light emitting diodes (LED) was experimentally studied. The strain was produced either by axial pressure or by indentation with a Wickers pyramid. We show that degradation affects the degree of polarization and the far-field distribution of laser emission. The effect of strain on the degradation intensity is estimated.

Dynamic properties of polar states initiated by inhomogeneous heating of crystals in all 20 piezoelectric classes are studied. Production mechanisms of the primary, secondary and tertiary polarization components under nonequilibrium thermal conditions are discussed. Inertial properties of induced polar states along with external factors is demonstrated to govern inertial properties of sensors operating on the tertiary pyroelectric effect. Possible inertia mechanisms of the tertiary pyroelectric effect associated with flexure, high- frequency vibrations of the crystal plate as well as a heat diffusion in it are analyzed theoretically and experimentally extensively. The conditions for a correct measurement of temporal and energy characteristics of a laser radiation are determined.

The comparative study of absorbing coating for LiNbO₃ based sensitive elements of pyroelectric detectors of radiation formed from metal and dielectric blacks and thin film metal-dielectric SiO<Cu>composites has been performed. Prospects of using composite SiO<Cu>metal- dielectric films for pyroelectric application are shown.

Photodiodes with p-n junctions formed by ion etching of p-Hg_1-xMn_xTe (x approximately equals 0.1) are reported. The absorption curves of the crystals found from optical measurements are treated within the Kane theory for semiconductors with highly nonparabolic energy bands. The diode responsivity spectra are interpreted in the framework of model taking into account the generation of photocarriers in -regions as well as in the depletion layer. The diode photoresponsivity in the region of the photon energies below semiconductor bandgap is shown to be caused by the gentle slope of the observed absorption edge.

The photocurrent spectra are investigated in Hg_1-xCd_xTe liquid phase epitaxy (LPE) films and photodiodes of n + -p type on their base with composition gradient. The LPE films were grown on CdTe and CdZnTe single crystal substrates. The transformation of the photocurrent spectra caused by the composition gradient is studied both experimentally and theoretically. The analytical expressions for the spectral dependencies of the photocurrent are derived from the solution of the one-dimensional continuity equation. The calculation of the photocurrent spectra are made in which the nonparabolicity of the energy bands HgCdTe is taking into account.

In review articles the methods of preparation as well as basic properties of ohmic contacts metal-semiconductors A₃B₅ are generalized. Chemical treatment of n-InAs result in pinning of a Fermi level by surface states in a conduction band. Thus, the near-surface area is enriched by majority carriers. The deposition of a metal on n-InAs with tunnel- transparent native oxide results in structures with an antiblocking contact. In chemically treated samples of p-InAs the pinning of a Fermi level in a conduction band causes a strong band bending of an order of the gap's width of InAs and formation of an inversion layer. The deposition of a metal on p-InAs transforms this structure into an imperfect Schottky diode, the height of a potential barrier in which does not depend on a work function of a metal. For transformation of rectifying structure metal-p-InAs into non-rectifying with linear current-voltage characteristics the formation of highly doped near-surface p +-InAs layer is used by means of epitaxial growth, or thermal diffusion of an acceptor impurity, such as Zn with its high solubility in InAs. The availability p+-InAs layer results in tunnel current mechanism through a depletion region, linear current-voltage characteristic and decrease of a contact resistance. The contact material to p+-type layer in the case of its epitaxial growth is Ti in the structure Au/Ti or Be in the structure Au/Be. The necessity of thermal treatment of such contacts was not indicated. In the case of diffusive formation of p+--area, as a rule, the alloys on the basis of indium In-Zn<5%> or In- Ni<1%>Zn<9%> are deposited by thermal evaporation followed by the thermal treatment. However, the temperature of the treatment was unknown in these articles. It should be pointed out that imperfect contacts can influence the magnitude of a noise and its frequency dependence and, therefore, the values of the detectivity of InAs photodiodes. In accordance with the above-stated, the purpose of the present work is to study influence of thermal treatment of In/Zn/p-InAs, In/n-InAs structures on their electrical and noise performances and finding-out capability of formation of low-noise ohmic contacts to p- and n-InAs materials.

The review including personal input of the authors is devoted to the theoretical basis and experimental researches of ferromagnetic and ferroelectrics phase transitions in IV-VI semiconductors. The exclusive role of manganese in promoting of ferromagnetic interaction is shown. The magnetic phenomena in Pb_1-XSn_XTe doped by manganese and in solid solutions Pb_1-X-YSn_XMn_yTe are outlined. These phenomena include the appearance the exchange thermoelectric power (TP), the additional TP, promoted by electron scattering on magnetic centers, ferromagnetic ordering at high hole concentration by the appearance of anomalous Hall effect and negative resistivity. The theoretical considerations of ferroelectric structural transitions (ST) due to electron- phonon interband interaction and ordering of the dipoles obliged to noncentral ions are outlined. The author's data about the effect of ST on magnetic susceptibility (MS) and TP are described. The first observations of paramagnetic splashes of MS at ST, breaks or bends on TP temperature dependences, the existence of hysteresis phenomena, the influence of the degeneration of electron gas on TP are described. The ideas concerning the applications of diluted magnetic semiconductors in magnetoelectronic devices are outlined.

Polarization dependent photoluminescence (PL), time-resolved PL and PL excitation experiments are performed in order to clarify the origin of the linear polarization of the PL of porous Silicon excited by linear polarized light. It is shown that this effect, when PL is excited significantly above the detection energy, is not related to a coherent exciton alignment or selective optical excitation of those nanocrystals whose transition dipole moments are oriented parallel to the polarization vector of the exciting light. The experimental results are interpreted in the framework of a dielectric model assuming aspheric nanocrystals.

The influence of a light hole band nonparabolicity on the transport properties of Cd_xHg_1-xTe and InSb in both intrinsic and extrinsic conductivity regions is investigated. The parameters of heavy and light holes (concentration and mobility) for homogeneous samples of p-Cd_xHg_1-xTe (x equals 0,2 - 0,23) are determined from the Hall coefficient field dependencies. These parameters and similar data for InSb available in the literature have been compared with results of analytical computations based on the recent concepts of material parameters.

Photoluminescence (PL) in complex micropore-macropore silicon structures consisted of 100 - 700 nm micropore layers on macropore walls have been studied. Scanning electron microscopy observations and Fourier transform infrared spectroscopy results have been performed to identify structure and local chemical states. For higher current densities during pore formation the intensity of orange PL peaking near 600 nm decreased, and the PL lifetime was grown. The blue PL shift was observed due to reduction of Si nanoparticle sizes, and micropore-macropore structures showed the lower PL intensity dealing with the small hydride concentration and thin microporous layers. Obtained results suggest arising of orange PL from microporous layers on the macropore walls that widened optoelectronic functions of two-dimensional macroporous silicon structures.

It was shown, that the uniaxial compression leads to the increase of Auger lifetimes in the narrow gap semi-conductors, and to the decrease of the radiative band to band lifetimes. The quantum efficiency can be increased up to 1 on the base of this effect. Experimental results are obtained for InSb an HgCdTe.

Negative luminescence (NL) operation at approximately 4 micrometer is reported for p-InAsSbP/n-InAs reverse biased diodes with efficiency of about 60% (180 degrees Celsius). High NL conversion efficiency (25 mWcm^-2A^-1, 180 degrees Celsius) and remarkable value of negative apparent temperature ((Delta) T approximately equals -6 degrees Celsius) show advantages of p-InAsSbP/n-InAs NL devices for high temperature applications.

The procedure of Rutherford backscattering spectrometry (RBS) is worked out for following goals: firstly, investigation of stoichiometry damages of semiconductor subsurface layer after various methods of treatment; secondly, investigation the depth distribution of the components in semiconductor- insulator transition layer; thirdly, determination of components concentration in anodic oxide and transition layer depth. Taking into account the special features of the narrow- gap semiconductor-insulator structures we chose the optimum ion type and energy, scattering geometry, admission time of spectrum to except the heating, radiation damage and composition stoichiometry variation. With the RBS we have carried out the extensive investigations of influence of surface handling conditions, anode oxidation regimes on the properties of the metal-insulator-semiconductor (MIS) structures on the base of the narrow-gap semiconductors such as HgCdTe (MCT), HgMnTe (MMT) and HgZnTe (MZT) having various compositions and electric parameters.

The angular distribution of the annihilation photons (ADAP) and positron lifetime measurements have been carried out to study of vacancy-type defects in samples of Hg_1-xCd_xTe (MCT). It was found that ADAP curve parameters for as-grown MCT crystal are very different from ones for low defect samples. The values of the annihilation rate in the bulk state and in the V'_Hg trapped state were obtained as 3.55 ns^-1 and 3.13 ns^-1, respectively. The specific positron trapping rate v was estimated to be 5 (DOT) 10^-7 cm³s^-1.

We investigate the temperature and the magnetic field dependences of magnetic susceptibility of Pb_1-xGe_xTe(0Yb3+ and nonmagnetic Yb²⁺ ions in the alloys and the possibility of transition of ions from one state to the other due to shift of the Yb impurity level with respect to the valence band edge as the composition of the alloy changes.

The temperature dependences of electrical resistivity (rho) and thermoelectric power S for the SnTe polycrystalline thin films with charge carrier concentration of (3 - 5)(DOT)10²¹ cm^-3 have been obtained in the range of 80 - 300 K. It was established that the (rho) (T) and S (T) dependences had non-monotonous character. In the temperature range of (80 - 150) K series of peculiarities in the form of steps and plateaux were observed most distinctly. Assumptions about the nature of these anomalies were made. The possible reasons for appearance of numerous temperature peculiarities are system's passing through different quantum states; the processes of self-organization taking place in an open system (heated thin film) at definite levels of excitation (certain temperatures); microdomain structure of thin films; relaxation processes. The pronounced anomalies observed in the temperature ranges of 135 - 150 and 190 - 200 K were attributed to phase transitions caused by redistribution of non-stoichiometric defects.

The temperature dependences of electrical conductivity (sigma) , Hall coefficient R_H and charge carrier mobility (mu) _H were obtained for the Pb_1-XMn_XTe solid solutions (x equals 0 divided by 0.025) in the range of 80 - 300 K. On the basis of the temperature dependences of (mu) _H, isotherms of charge carrier mobility were plotted. In all the isotherms there was observed anomalous growth in (mu) _H in the concentration range of x equals 0.0075 divided by 0.0125. The analogous anomaly was detected in the concentration dependences of power coefficient b in the temperature dependence of mobility (mu) _H equals A(DOT)T^-b. The revealed anomalies in the concentration dependences of properties are attributed to critical phenomena of percolation type taking place in any solid solution under transition from diluted solid solutions to concentrated ones.

The role of deep defect states in recombination processes of narrow-gap IV-VI semiconductors is discussed. Earlier several defect states in the gap of IV-VI semiconductors were revealed. Estimations have shown that defect levels nearer to c-band presumably are connected with metal-rich microinclusions by diameter about 1300 angstrom. These metal- rich inclusions are the result of low metal vacancies enthalpy formation ((Delta) v approximately equals 0.35 eV). These defect states seem are arising at the inclusions and semiconductor matrix boundaries. The density and the diameter of these intrinsic metal microinclusions were calculated from the results of magnetic susceptibility by SQUID-magnetometry experiments in the 1.7 - 20 K temperature region. The levels above the v- band, with the density of states about 3 times lower compared to density of states below c-band, seem to be connected with Te-rich microclusters. The enthalpy of Te-vacancies formation is about 0.45 eV. Experiments and estimations fulfilled on defect levels position and concentrations allow to explain the experiments on band-to-band recombination, photoconductivity and relaxation measurements, stimulated recombination between defect level and v-band, and some nonlinear effects in these semiconductors.

The possibility of defect structure and consequently basic parameters (carrier density, their mobility and lifetimes) control in bulk mercury-cadmium telluride (MCT) using the nanosecond laser irradiation induced shock waves (LSW) is investigated. MCT bulk samples (with composition x equals 0.2) both n- and p- type with different initial structural quality were treated. The post-treatment changes have been detected by galvanomagnetic and photoelectric (lifetime) techniques. Two depending of irradiation mode mechanisms of interaction between LSW and bulk Hg_1-XCd_XTe defect subsystem are given. The potentiality of this technique as a technological tool for controlled modification of MCT parameters is discussed.

The influence of the plastic deformation on the magnetic susceptibility of molybdenum and zinc has been studied. It is found that a sharp increase of the paramagnetic susceptibility after the compression deformation essentially depends on the state of the crystal surface before deformation. The chemical removal of the surface layer leads to disappearing of the observed effect. A concept of connection of arising unusual magnetic behavior of molybdenum and zinc with appearance of microcracks in the surface layer under deformation is proposed. Microcracks are supposed to lead to anomalously high magnitudes of the magnetic susceptibility.

Dependencies of the lattice constant and the magnetic susceptibility on the composition of (InSb)_1-x(CdTe)_x solid solution have been studied. Anomalous behavior of the magnetic susceptibility at weak magnetic fields was observed. The correlation between changes of the lattice constant and magnetic properties has been analyzed. The possibility of the semiconductor-metal transition has been discussed.

Cadmium telluride and cadmium selenide crystals being important materials for Infrared Photoelectronics are extremely ductile at room temperature and their ductility remains down to temperature 77 K. Therefore during several processing stages as well as at device operating the dislocations and other deformation defects are introduced into the semiconductor materials. In this work it has been shown that the generation and travel of dislocations give rise two series of the characteristic emission which are principally differed one from another. At low temperature (T<100 K) the dislocation movement gives rise to the metastable characteristic emission lines with small width. It has been shown that new emission lines arise due to the generation of intrinsic point defects in the form of some one-dimensional extended structures during dislocation slip. The low temperature prevents the disordering of these structures. On the other hand simultaneously the dislocation travel gives rise to another characteristic photoemission lines. These lines are stable and directly connected with the dislocation core electron states.

The theoretical description of the 'dynamic halo' -- the specific scattering cone is presented. This effect was found in LiTaO₃ crystals doped with Cr under steady-state laser illumination. The main distinctive features of the scattering, namely the conic spatial structure and temporal evolution have been successfully considered within the framework of the theory. Our approach is based on the linearization of equations for wave-coupling in photorefractive media with linear electro-optic effect and local (photovoltaic) response. We take into account interactions between two waves: the strong pumping wave and the weak forward-scattering wave. The random inhomogeneities of refractive index occurred due to the small dynamic fluctuations in the photovoltaic impurity distribution were considered as the scattering seeds. The temporal evolution of the halo amplification exists due to the photovoltaic current. The weak scattering wave arises near the front plane of the crystal and reinforces inside its depth. We have obtained qualitatively agreement of our theory with the experiments for the thick crystals.

The molecular beam epitaxy (MBE) set-up with analytical control equipment of growth process was designed and fabricated for growing A²B⁶ compounds including the mercury-containing ones. A technology was elaborated for growing mercury-cadmium-telluride (MCT) solid solution heteroepitaxial structures (HS) by molecular beam epitaxy (MBE) method with a given variation of MCT composition throughout the thickness. HS's MCT MBE on CdZnTe/GaAs substrate with different variation composition in layers at MCT film interfaces were designing and growing. These structures were used for manufacture of high quality single, linear and array photoconductors (PC) and photodiodes (PD) operating at 77 K and 200 - 250 K temperature in the wavelength range of 3 - 5 micrometer and 8 - 12 micrometer, up and over 20 micrometer. Widegap layers at MCT film interfaces are used as passivating coating. Narrowgap layer at MCT film/CdZnTe buffer layers interface is used for decrease of PD series resistance. For decrease of dark currents of photodiodes array operating at 200 K HS MCT MBE were used with special composition distribution of composition throughout the thickness.

In this report a brief review of the semi-intrinsic conductivity phenomenon in doped CdTe:Cl, CdTe:Ga and Cd_{1- x}Zn_xTe materials used for room temperature X and (gamma) -ray detectors is discussed. The upper limit of the resistivity is analyzed in a framework of a general three- levels Fermi-statistic model. The role of the residual impurities and impurity-defect interaction as well as segregation of impurity in Te inclusions are discussed. Dependence of the elementary native defects energy formation on the Fermi-level position in CdTe is shown and some reactions between them are taken into consideration for the Fermi-level stabilization near the middle of the band-gap. On the bases of the Fermi-level stabilization phenomenon it is shown that a self-compensation and a maximum doping level in CdTe:Cl, CdTe:Ga and Cd_1-xZn_xTe depend on the absolute energy of the C (V)-band position. Experimental results of EDAX compositional measurements, photoluminescence are used for illustration of these problems.

The nature of CdTe, Cd_1-XZn_XTe solid solutions, InAs and InSb dissolution in the mixture of HNO₃-HCl-lactic acid system are investigated. The surfaces of equal etching rates (Gibbs diagrams) are constructed, limiting stages of dissolution process and regions of polishing solutions in this system are determined.

A possibility of CdTe substrate purification from impurities by structure-breakdown layer gettering, formed by laser irradiation, is considered. For profile calculation of diffusive distribution of point defects during heat treatment, and also substrate purification degree after heat treatment, a model, based on diffusion equation with consideration of impurity absorption by dislocations, is proposed. Impurity redistribution task in structure CdTe-CdHgTe during annealing is solved also. Investigations, carried out on specially prepared samples, confirmed CdTe purification effectiveness by gettering: impurity concentration decreased in 5 - 10 times.

It is considered the possibility to register radiant flows with the help of transverse thermo-emf, arising in devices on anisotropic semiconductors with different degree of optical radiation transmission, called the anisotropic optical thermoelements (AOT). It is showed, that in case of optical transmission regime and triangular form of AOT cross-section, the possibility to control radiant flows with its simultaneous turn on given angular in visible and IR-regions of spectrum exists.

Four main multilayer coatings are manufactured. Different combinations of these coatings allow to solve various tasks connected with the filtration of middle range infrared light. The cut-on coatings are the base of the construction, which divided all spectrum in two different parts: high transmission and full blocking. In order to obtain a cut-on filter with good transmission and rejection characteristics, it was necessary to coat both sides of the substrate. One multilayer serves as the principal high-pass stack and the auxiliary -- to achieve full blocking. The design, manufacture and optimum performance of coatings is discussed. The coatings are composed of PbTe/ZnS symmetric stacks deposited on two sides of a ZnSe(ZnS) or germanium substrate. Transmission characteristics of the different infrared interference filters are presented. It is shown that the set of materials which was chosen for such kind of coatings made it possible to get both steady optics characteristics from room temperature up to 4.2 K, high mechanical and thermal stability, as many property, which we need for cryogenic cooling: to realize stable layer in vacuum; good adhesion; dilatometric compatibility without hydroscopicity. The coatings are very simple. They contain the layers of two materials and final principal multilayers contain only ten layers. The coatings were tested on thermal and mechanical stability.

CdTe, Cd_XHg_1-XTe (x equals 0.1), and PbTe whiskers were grown by chemical transport reaction (CTR) method in closed system. An investigation of growth kinetics and morphology of the whiskers shows that they grow according to both vapor-liquid-solid (VLS) and vapor-crystal (VC) mechanisms. The dependencies of resistivity and photoconductivity on the whisker diameter were found and discussed. Some structure imperfections in the whiskers of large diameters (d > 100 micrometer) are assumed to be present.

The structure of Mn_xHg_1-xTe thin layers with x equals 0.12 - 0.19 deposited on CdTe substrates with (111) and (110) orientations has been investigated. The glow radio-frequency (RF) (f equals 13.56 MHz) discharge was excited according to the diode scheme in magnetic field. The process was carried out under Hg vapor pressure from 5 (DOT) 10^-3 to 8 (DOT) 10^-3 Torr with quasiclosed volume. The possibility of Hg vapor pressure regulation allowed to carry out reactive process of MnHgTe layers condensation. It has been shown, that RF sputtering of MnHgTe in mercury glow discharge permits to obtain epitaxial layers with perfect structure. Optimal values of substrate temperatures which lead to epitaxial growth are from 230 to 250 degrees Celsius. The carrier concentrations and their mobilities have been determined.

Mn_xHg_1-xTe (x equals 0.1 - 0.13) layers were deposited on CdTe (111) substrates from Mn_xHg_1-xTe (average composition of x equals 0.14) by a pulsed YAG:Nd laser with scanning of the laser beam over the source material. Layers were deposited at different substrate temperatures (from the room temperature to 250 degrees Celsius). It has been established that epitaxial growth of Mn_xHg_1-xTe layers occurs in the narrow range of substrate temperature from 180 to 200 degrees Celsius. As-grown layers are n-type with electron mobility of (mu) equals (0.7-2.8)X10³ cm²/Vc and electron concentration of n equals(0.6 - 3.0)X10¹⁷ cm^-3 at 77K. Thermal treatment in Hg overpressure has been founded to almost unchange the carrier concentration of the layers. The abrupt increase of the carrier mobility (up to 1.5 order of magnitude) is achieved after two-stage heat treatment in Hg overpressure.

In this paper we present the experimental results on kinetic research of a gas phase formation in the system Ga/In-AsCl₃-HCl-H₂ which we use for the preparation of high quality InP/InGaAs multilayers with thickness less than 100 nm by I -VPE method. This experimental data are received in-situ by UV-spectroscopy when combined In-Ga source is used. The analysis of kinetic processes in a zone of the source is necessary to understand the influence of such parameters as temperature, gas carrier flow rates, In/Ga source surface area, input concentrations of chloride containing components on composition of gas phase. It is shown that the going completeness of the heterogeneous reactions strongly depends on the Ga-In source surface area and input flow rate under other equal parameters. Besides analyzing of the gas phase composition it is necessary to take into account GaCl _(liq.) equals GaCl _(g) equilibrium at the temperature below 800 K.

Dissolution of InAs in the K₂Cr₂O₇-HBr-HCl (oxalic acid) solutions is studied in reproducible hydrodynamics conditions. The surfaces of equal etching rate are constructed using mathematical planning of experiment, and the limiting stages of the dissolution process are determined. The kinetic behavior of indicated semiconductors depending on the mixing rate and temperature of solution was investigated and it was shown that the dissolution of these semiconductor compounds in the solutions of the investigated systems is limited by the diffusion stages. The dissolution rates of InSb in such solutions distinguish weakly from each other and are within the interval of 0.5 - 6 micrometer/min. The solutions of K₂Cr₂O₇-HBr-HCl (oxalic acid) systems can be employed for the developing of polishing solutions for the indium antimonide treatment with small etching rate.

For a case of chemical reactions of the first order the mathematical model of process of chemical cutting of crystals is advanced. It is showed, that the return speed of chemical cutting is equal to the sum of return speeds of such values, as velocity of a chemical reaction, velocity of delivery etchant and speed of diffusion of molecules of a reactant. At research of process of chemical cutting of crystals InSb the satisfactory coordination between experimental and theoretical results is obtained. The developed model can be used at designing of the equipment and for optimization of process of chemical cut.