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A study of the electroluminescence of asymmetric InAs/InAs1 – ySby/InAsSbP light-emitting diode heterostructures with a molar fraction of InSb in the ternary solid solution in the active region y = 0.15 and y = 0.16 in the temperature range 4.2–300 K is reported. It is found on the basis of experimental data that a staggered type-II heterojunction is formed at the InAs1 – ySby/InAs0.41Sb0.28P0.40 heterointerface. It is shown that interfacial radiative transitions at the type-II heterointerface make a dominant contribution in the temperature range of 4.2–180 K. This enables minimization of the temperature dependence of the operating wavelength of a light-emitting diode.

The results of studying the optical transmission, photoconductivity, photoluminescence, and X-ray diffraction of HgCdTe solid-solution samples with a high content of CdTe (molar fraction 0.7–0.8), grown by molecular-beam epitaxy (MBE) and liquid-phase epitaxy (LPE), are presented. It is shown that the material under study shows a significant degree of disorder of the solid solution, which is greater in structures grown by MBE on GaAs substrates, compared with the LPE-grown films. A study of the photoluminescence reveals states in the band gap, previously considered untypical of HgCdTe films grown on GaAs substrates, but typical only of films grown on Si. On the whole, the high quality of the material with a high CdTe content, grown by MBE and used to create the HgTe/HgCdTe nanostructures currently in high demand, is confirmed.

The spectral parameters of midinfrared LED heterostructures with an InAs active region were studied experimentally, calculated using MATLAB, and simulated in COMSOL Multiphysics. The obtained data were compared to reveal the mechanism of formation of the emission spectra of these heterostructures. The results confirm that simulation is a promising design tool for LED structures.

The capabilities of metalorganic vapor-phase epitaxy (MOVPE) in fabrication of structures with thin (1–2 nm) alternating InAs/GaSb layers on a GaSb substrate are studied. The characteristics of these structures were examined using transmission electron microscopy and methods of photo- and electroluminescence. It was found that two GaInAsSb solid solutions of different compositions were formed in the active regions of structures in the given growth conditions. The fabricated system was characterized by an emission wavelength of 4.96 μm at a temperature of 77 K. The results reveal new opportunities for bandgap engineering of semiconductor structures based on InAs/GaSb, which are designed for optoelectronic devices operating in the infrared range, provided by MOVPE.

The disordering in cadmium mercury telluride solid solution films grown by molecular beam epitaxy on Si and GaAs substrates has been examined by optical transmission and photoluminescence investigations. The effect of a fundamental decrease in the disordering scale under thermal annealing and possible interplay of the observed phenomena with defects typical of films grown by molecular beam epitaxy are discussed.

Expressions for the Auger- and radiative-recombination rates are derived in terms of Kane’s model for materials with a band-gap width close to the spin-orbit splitting energy, which is the case for InAs, InAsSb solid solutions, etc. Our results are compared with simplified expressions for recombination rates, frequently used in publications. It is shown that the nonparabolicity of the electronic structure should be taken into account in calculations of the recombination rates. As an example, the temperature dependences of the charge-carrier lifetimes governed by radiative and non-radiative processes are calculated for InAsSb solid solutions.

The first results showing the possibility of manufacturing InAs/GaSb superlattices by the metal-organic chemical vapor deposition (MOCVD) method are presented. The possibility of manufacturing heterostructures with an InAs/GaSb strained superlattice with layer thicknesses of 2–4 nm is experimentally demonstrated. The 77-K electroluminescence spectra of the structures show a long-wavelength peak at around 5.0 μm (0.25 eV). This peak is probably associated with the strained superlattice because solid solutions that could form on the basis of composite compounds do not provide this carrier-recombination energy.

Properties of HgCdTe films grown by molecular beam epitaxy on GaAs and Si substrates have been studied by performing variable-temperature photoluminescence (PL) measurements. A substantial difference in defect structure between films grown on GaAs (013) and Si (013) substrates was revealed. HgCdTe/GaAs films were mostly free of defect-related energy levels within the bandgap, which was confirmed by PL and carrier lifetime measurements. By contrast, the properties of HgCdTe/Si films are affected by uncontrolled point defects. These could not be always associated with typical “intrinsic” HgCdTe defects, such as mercury vacancies, so consideration of other defects, possibly inherent in HgCdTe/Si structures, was required. The post-growth annealing was found to have a positive effect on the defect structure by reducing the full-widths at half-maximum of excitonic PL lines for both types of films and lowering the concentration of defects specific to HgCdTe/Si.

Photoluminescence and X-ray diffraction (XRD) were used for the studies of the properties of HgCdTe samples with CdTe molar fraction x=0.3 grown by various methods. According to the results of photoluminescence studies, all samples possessed a considerable degree of alloy disorder, yet the scale of the disorder seemed not to be directly related to the structural quality of the material as revealed using XRD. Prospects of using HgCdTe material grown by various methods in optoelectronic devices are discussed.

Photoluminescence of HgCdTe epitaxial films and nanostructures and electroluminescence of InAs(Sb,P) light-emitting diode (LED) nanoheterostructures were studied. For HgCdTe-based structures, the presence of compositional fluctuations, which localized charge carriers, was established. A model, which described the effect of the fluctuations on the rate of the radiative recombination, the shape of luminescence spectra and the position of their peaks, was shown to describe experimental photoluminescence data quite reasonably. For InAs(Sb,P) LED nanoheterostructures, at low temperatures (4.2–100 K) stimulated emission was observed. This effect disappeared with the temperature increasing due to the resonant ‘switch-on’ of the Auger process involving transition of a hole to the spin-orbit-splitted band. Influence of other Auger processes on the emissive properties of the nanoheterostructures was also observed. Prospects of employing II–VI and III–V nanostructures in light-emitting devices operating in the mid-infrared part of the spectrum are discussed.

Electroluminescence of LED heterostructures with active layer made of InAsSb films grown on InAs substrates was studied in the temperature range T = 4.2–300 K. At low temperatures (T = 4.2–100 K), stimulated emission was observed with an optical cavity formed normal to the growth plane. The emission became spontaneous at higher temperatures due to the resonant “switch-on” of the CHHS Auger recombination process in which the energy of a recombining electron-hole pair is transferred to a hole transitioning to the spin-orbit-splitted band. The spontaneous character of emission continued up to room temperature because of the influence of other Auger processes. The results obtained suggest that InAsSb-based LED heterostructures are promising for the fabrication of vertically-emitting mid-infrared lasers.

The photoluminescence of the epitaxial structures based on the narrow-gap CdHgTe solid solutions has been experimentally investigated and the presence of large-scale composition fluctuations localizing carriers in the structures has been established. A model has been proposed for describing the effect of the fluctuations on the radiative recombination rate, the shape of the luminescence spectra, and their peak position. The model describes carrier transport and recombination at the strongly inhomogeneous composition of the solid solution and demonstrates the manifestation of carrier localization in the luminescence spectra.

Optical and electrical characteristics of asymmetrical InAs/InAsSb/InAsSbP LED heterostructures with the InSb content in the active layer of 0.15 and 0.16 were studied in the temperature range 4.2 -300 K. At T < 150 K, radiative transitions involving donor-acceptor states in the InAs substrate were observed in electroluminescence spectra, and the presence of these states also showed up in the peculiarities of current-voltage characteristics. A strong effect of the quality of the InAsSb/InAsSbP heterointerface on the characteristics of the heterostructures was observed.

Results of photoluminescence studies of single-quantum-well HgCdTe-based structures and electroluminescence studies of multiple-quantum-well InAsSb-based structures are reported. HgCdTe structures were grown with molecular beam epitaxy on GaAs substrates. InAsSb-based structures were grown with metal-organic chemical vapor deposition on InAs substrates. The common feature of luminescence spectra of all the structures was the presence of peaks with the energy much larger than that of calculated optical transitions between the first quantization levels for electrons and heavy holes. Possibility of observation of optical transitions between the quantization levels of electrons and first and/or second heavy and light hole levels is discussed in the paper in relation to the specifics of the electronic structure of the materials under consideration.

Current-voltage characteristics of light-emitting diode heterostructures based on InAsSb epitaxial films and a multi quantum-well structure were studied in the temperature range T = 4.2–300 K. It is shown that transport through the heterostructures is governed by the diffusion and recombination mechanisms at temperatures close to 300 K. The tunnelling effect appears in the temperature range 4.2–77 K. The presence of quantum wells in the active layer results in increased diode leakage currents due to tunnelling.

Variable-temperature (4.2 - 300 K) electroluminescence (EL) studies were performed on two asymmetrical InAs/InAsSb/InAsSbP LED heterostructures emitting at 5.02 and 5.10 μm wavelengths at 300 K (with an InSb content in the active layer of 0.15 and 0.16, respectively). For the structure with the narrowest bandgap, a weak temperature dependence of the position of the EL peak was observed. Along with strong carrier localization in the active layer, which was provided by the design of the structure, this made the studied heterostructures promising for fabrication of LEDs with working wavelengths extending beyond 5 μm at 300 K.

Optical transmission and photoluminescence were used for the study of wide-bandgap (0.8-1.1 eV) HgCdTe (MCT) material grown by molecular-beam epitaxy. The material, including layers used as spacers and barriers in potential-and quantum-well structures, showed a considerable degree of alloy disorder similar to narrow-gap MCT grown by the same method. In some samples, defect states in the bandgap were found. Optimization of the growth technology for wide-bandgap material should help improving the quality of MCT-based potential-and quantum-well structures designed for various applications.

Subject of Study. We consider spectral characteristics of mid-infrared light-emitting diodes with heterostructures based on InAs(Sb,P) emitting at T=300 K in the wavelength range 3.4–4.1 micrometers. The aim of the study was to search for the ways of increasing the diode efficiency. Methods. The heterostructures were grown from metal-organic chemical compounds with the use of vapor-phase epitaxial technique. The spectra were recorded under pulse excitation with the use of computer-controlled installation employing MDR-23 grating monochromator and a lock-in amplifier. InSb photodiode was used as a detector. Comparative study of electroluminescence spectra of the diodes was carried out at the temperatures equal to 300 K and 77 K. We compared the obtained data with the calculation results of the band diagrams of the heterostructures. Main Results. As a result of comparative study of the electroluminescence spectra of the diodes recorded at 300 K and 77 K we have established that increasing of their efficiency is hindered by substantial influence of Auger recombination. For the first time at 77 К we have observed the effect of stimulated emission from InAsSb active layer in light-emitting structures made of InAs/InAsSb/InAsSbP. For heterostructures with quantum wells InAs/(InAs/InAsSb)/InAsSbP we have found out that at 77 К the carrier recombination occurs outside quantum wells, which points out to the insufficient carrier localization in the active layer. Thus, we have shown that the efficiency of mid-infrared light-emitting diodes based on InAs(Sb,P) can be increased via suppression of Auger-recombination and improvement of carrier localization in the active region. Practical Relevance. The results of the study can be used for development of heterostructures for mid-infrared light-emitting diodes.

A study of defects in HgCdTe films grown by molecular-beam epitaxy on GaAs and Si substrates was performed. Variable-temperature photoluminescence (PL) and carrier lifetime measurements were carried out on as-grown films and films subjected to post-growth annealings. Films grown on GaAs substrates appeared to be mostly free from defects providing energy states within the bandgap, yet specific acceptor states were generated in these films under conditions associated with mercury deficiency. The properties of films grown on Si substrates were mostly governed by two types of uncontrolled defects. Relatively deep levels with energy 40 to 70 meV were revealed with the use of PL measurements, yet their effect on the lifetime was not traced. The lifetime value was rather determined by other type of defects with energy depth of ∼30 meV. Possible relation of these defects to the specifics of MBE growth of HgCdTe on Si substrates is discussed. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Defects in mercury-cadmium-telluride heteroepitaxial structures (with 0.3 to 0.4 molar fraction of cadmium telluride) grown by molecular-beam epitaxy on silicon substrates are studied. The low-temperature photoluminescence method reveals that there are comparatively deep levels with energies of 50 to 60 meV and shallower levels with energies of 20 to 30 meV in the band gap. Analysis of the temperature dependence of the minority carrier lifetime demonstrates that this lifetime is controlled by energy levels with an energy of ∼30 meV. The possible relationship between energy states and crystal-structure defects is discussed.

The probability of the radiative recombination of carriers in narrow-gap semiconductors is analyzed for the example of Cd x Hg1–x Te solid solutions. Expressions are derived for the imaginary part of the dielectric permittivity in terms of the three-band Kane’s model with consideration for the nonparabolic dependence of the carrier energy on the wave vector. It is shown that taking into account this nonparabolicity of the energy spectrum of carriers modifies the dependence of the imaginary part of the dielectric permittivity on frequency. Expressions for the probability of radiative recombination, derived in terms of the simple parabolic model and Kane’s model with and without the nonparabolicity effect taken into account, are compared. It is shown that the contributions to recombination from electron transitions to heavy- and light-hole bands are close and the contribution from light holes cannot be neglected when calculating the radiative-recombination probability.

The temperature dependence of the carrier lifetime in CdxHg1 − xTe narrow-gap solid solutions in the temperature range 5 K < T < 300 K is analyzed within the scope of a microscopic model. Main attention is given to an analysis of the Auger recombination mechanism governing the carrier lifetime at high temperatures. The Auger-recombination rates are calculated with consideration for specific features of the band structure of the narrow-gap semiconductor in microscopic theory. It is shown that strict account of the non-parabolicity of the electronic structure in terms of Kane’s model leads to a substantially different temperature dependence of the Auger-recombination rates, compared with the approach in which nonparabolicity is disregarded.

The photoluminescence method is used to study acceptor states in CdHgTe heteroepitaxial films (HEFs) grown by molecular-beam epitaxy. A comparison of the photoluminescence spectra of HEFs grown on GaAs substrates (CdHgTe/GaAs) with the spectra of CdHgTe/Si HEFs demonstrates that acceptor states with energy depths of about 18 and 27 meV are specific to CdHgTe/GaAs HEFs. The possible nature of these states and its relation to the HEF synthesis conditions and, in particular, to the vacancy doping occurring under conditions of a mercury deficiency during the course of epitaxy and postgrowth processing are discussed.

The impurity-defect structure of heteroepitaxial Cd x Hg1 − x Te/Si (0.35 < x < 0.39) layers grown by molecular beam epitaxy for the creation of arsenic-ion-implanted p +-n junctions has been studied by the photoluminescence method. It is established that full realization of the possibilities of p +-on-n photodiode structures based on the CdHgTe/Si system is hindered by uncontrolled doping of the material that leads to the formation of both shallow (impurity level energy ∼10 meV) and deep (∼50 meV) acceptor levels.

Optical transmission, photoluminescence, and X-ray diffraction have been used for studying structural disorder in Hg1-xCdxTe (x=0.3–0.4) films grown by Molecular-Beam Epitaxy on GaAs and Si substrates. According to all three methods, studied films immediately after the growth showed quite different scale of the disorder. After thermal annealing films showed similar optical properties, yet their structural properties remained different. It appears that the ability of Hg1-xCdxTe to gain good optical quality under annealing for considerably disordered initial material is not directly structure-related.

This work demonstrates the possibility of growing Type-II InAs/GaSb superlattices by MOCVD. The Type-II InAs/GaSb superlattices consisting of 20 pairs of alternating InAs and GaSb layers of equal thickness (1 nm / 2 nm) were grown at a temperature of 500°C. The obtained structures were studied by transmission electron microscopy and electroluminescence. The electroluminescence spectra demonstrated a maximum at about 0.25 eV.

The photoluminescence (PL) of CdHgTe solid solutions subjected to low-energy ion treatment is studied. A blue shift of the peaks in the PL spectra is observed immediately after ion treatment, which is attributed to the formation of a high concentration of donor defects and to the Burstein-Moss effect. The change in the shape of the PL spectra and, in particular, the disappearance of lines associated with transitions to acceptor states indicate that these defects are formed by the interaction of interstitial mercury atoms introduced into the sample during the course of treatment with impurity atoms. As the treatment is terminated, the electron concentration decreases due to the disintegration of defects and the blue shift disappears, but the shape of the spectra remains unchanged. This behavior of the PL spectra can be used for diagnostics of the defect-impurity structure of CdHgTe.

The spectra of the high-temperature (up to 300 K) photoluminescence of the heteroepitaxial structures based on the CdHgTe solid solutions that are grown using molecular-beam epitaxy and emit at room temperature in the wavelength interval λ = 1.5–4.3 μm are analyzed. It is demonstrated that the observed photoluminescence of the CdHgTe narrow-gap semiconductor at high temperatures and the specific features of the high-temperature spectra can be interpreted using the disorder of the solid solution as in the case of the solid solutions of the group-III nitrides.

The electrical and optical properties of epitaxial CdHgTe films grown on silicon substrates by molecular-beam epitaxy have been studied. The results of photoluminescence measurements are indicative of the high structural perfection of the films, and Hall data combined with low-energy ion treatment point to a low concentration of residual donors (∼5 × 1014 cm−3). Acceptor states supposedly related to the capture of impurities at structural defects typical of strongly lattice-mismatched heteroepitaxial structures are found in the films.

The problem of recording the photoresponse spectra in semiconductors with the persistent photoconductivity effect is considered for heterostructures with “slow” charge states at the heterointerface. The proposed versions of the solution of this problem include the use of modulation of excitation or reconstruction of the true shape of the spectrum recorded in the direct-current mode.

Quantum-confinement levels in a CdxHg1 − xTe-based rectangular quantum well are calculated in the framework of the four-band Kane model taking into account mixing between the states of electrons and three types of holes (heavy, light, and spin-split holes). Comparison of the calculation results with experimental data on the photoluminescence of CdxHg1 − xTe-based quantum wells suggests that optical transitions involving the conduction and light-hole bands are possibly observed in the spectra.

Photoluminescence (PL) of Hg1 − x Cd x Te-based heterostructures grown by molecular-beam epitaxy (MBE) on GaAs and Si substrates has been studied. It is shown that a pronounced disruption of the long-range order in the crystal lattice is characteristic of structures of this kind. It is demonstrated that the observed disordering is mostly due to the nonequilibrium nature of MBE and can be partly eliminated by postgrowth thermal annealing. Low-temperature spectra of epitaxial layers and structures with wide potential wells are dominated by the recombination peak of an exciton localized in density-of-states tails; the energy of this peak is substantially lower than the energy gap. In quantum-well (QW) structures at low temperatures, the main PL peak is due to carrier recombination between QW levels and the energy of the emitted photon is strictly determined by the effective (with the QW levels taken into account) energy gap.

We have studied the photoluminescence (PL) spectra of Cd x Hg1 − x Te/Cd y Hg1 − y Te nanohetero-structures grown by molecular beam epitaxy on CdTe/ZnTe/GaAs substrates. The width of potential wells in the structures was varied within d = 12−200 nm and the material composition was changed within x ∼ 0.25–0.40 in the well and y ∼ 0.68–0.82 in the barrier layers. The PL spectra of samples with d ≤ 33 nm exhibit transitions between quantum confinement levels. The samples with d > 50 nm display the PL due to excitons localized on composition fluctuations, which is characteristic of Cd x Hg1 − x Te epilayers with thicknesses above 3 μm. It is established that the exciton PL band in Cd x Hg1 − x Te exhibit broadening that is determined both by stochastic fluctuations of the composition and by its macroscopic inhomogeneities.

Hg 1-x Cd x Te samples with x=0.38 and 0.57 fabricated by molecular beam epitaxy, both as-grown and after annealing, were studied. Photoluminescence (PL) was measured in the temperature range 4.2 < T< 300 K. The PL peak energy was found to be less than that of the energy gap by a certain value δE that depended on temperature. This effect was attributed to recombination of excitons localized at composition non-homogeneities. An analysis was carried out that provided a way for evaluation of a non-homogeneity measure. The amplitude of the non-homogeneities was shown to decrease by about 50% as a result of post-growth annealing in a He atmosphere and Hg vapour.

We have studied the influence of various postgrowth treatments (annealing in helium atmosphere or mercury vapor, low-energy ion etching) on the optical and photoelectrical properties of mercury cadmium telluride (CdxHg1 − xTe) heteroepitaxial structures for the photo- and optoelectronic devices operating in the middle infrared range (3–5 μm). It is established that the annealing in mercury vapor is optimum for improving the photoluminescence characteristics in this range.

The spatial and temporal dispersion of the dielectric function of the electron gas in quasi-2D quantum nanostructures has been studied. Analytical expressions for the dielectric function for a quantum well in the form of a δ function and a rectangular well of finite depth are derived for the first time. A criterion for transition to strictly 2D and strictly 3D cases was obtained.

The effect of intraband carrier relaxation on the threshold characteristics of InGaAsP quantum well (QW) lasers is studied. The dependence of the intraband hole-hole relaxation time τ int on temperature and carrier density is analyzed. It is shown that taking into account the finiteness of τ int and its dependence on temperature and carrier density strongly affects the gain and the threshold current density of QW lasers.

Electroluminescence of mid-infrared LEDs with active layer made of InAs and InAsSb in a wide temperature range (4.2–300 K) was studied. At low temperatures (T=4.2–100 K), stimulated emission from the LEDs was observed. The emission became spontaneous at higher temperatures due to the effect of CHHS Auger recombination process, when the energy of a recombining electron-hole pair was transferred to another hole with the latter transitioning to the spin-orbit-splitted band. The spontaneous character of recombination held up to the room temperature due to the effect of other Auger processes. Still, the results obtained show that structures based on InAsSb are a promising material for fabrication of mid-infrared lasers.

Electroluminescence of InAs(Sb,P) heterostructures grown on InAs substrates was studied in the temperature range T = 4.2−300 K. At low temperatures (T = 4.2−50 K), stimulated emission was observed. This effect was due to optical resonator, which was formed between the lower face of the LED chip with the solid metal contact and the upper face with semiconductor/air interface. The emission became spontaneous at higher temperatures due to the effect of CHHS Auger recombination process, when the energy of a recombining electron-hole pair was transferred to another hole with the latter transitioning to the spin-orbit-splitted band. The results obtained show that structures based on InAs(Sb,P) are a promising material for fabrication of vertical-emitting mid-infrared lasers.

The first observation of photoconductivity (PC) in porous GaN layers fabricated by surface anodization of 0.6 μm thick GaN layers grown by HVPE on 6H-SiC substrates is reported. PC was studied at room temperature and a strong photoresponse was observed in anodized GaN layers, whereas no photoconduction in initial (not anodized) epitaxial layers was detected. Both the buildup and the decay of the PC in anodized GaN demonstrated exponential behavior with two time constants of 1.8 and 100 s, respectively. PC spectra of anodized GaN showed a steady increase of the photoresponse as the photon energy was increased from 2.5 to 3 eV. Room and low temperature (15 K) photoluminescence studies were also performed on initial and anodized structures. EBIC measurements showed formation of a barrier on the GaN/SiC interface after anodization. Photoresponse in anodized GaN layers is ascribed to a decrease in carrier concentration in the anodized semiconductor.

The equilibrium energy-band diagram of a broken-gap p-GaInAsSb/p-InAs heterojunction was calculated by solving the Poisson equation with account of the charge of free carriers and ionized impurities and the built-in charge at the heterointerface. The quantum level energies were found within the quasi-classical approximation for electrons in the self-consistent potential well. The calculated energies are close to those observed in electroluminescence spectra of such heterojunctions.

Photoconductivity and photoluminescence of HgCdTe-based nanostructures with 50 to 200 nm-wide potential wells were studied. The structures were grown by molecular beam epitaxy on GaAs substrates, and emitted light with wavelengths 2.8–3.8 μm at 300 K. The luminescence properties of the nanostructures at low temperatures were found to be strongly affected by the effect of alloy disorder, which led to a substantial red-shift of the emission spectrum in relation to energy gap of the wells. This effect could be reduced by post-growth annealing of the structures, which also increased the luminescence intensity. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Infrared photoluminescence (PL) measurements were used to probe compositional disorder in semiconductor (Hg,Cd)Te alloy. PL was studied in Hg1−xCdxTe samples with x=0.38 and 0.57, fabricated by molecular beam epitaxy on GaAs substrates. Both as-grown and annealed in Hg vapor and in He atmosphere samples were studied. In all the samples, the PL peak energy was found to be red-shifted from the position of band-to-band recombination maximum expected from the energy gap of the material. The value of the shift depended on temperature. This effect was attributed to recombination of excitons localized at compositional fluctuations, and an analysis was carried out that provided a way for evaluation of a fluctuation measure. The amplitude of the fluctuations was shown to strongly decrease as a result of post-growth annealing.

We have studied electroluminescence in n-GaSb/n-AlGaAsSb/n-GaInAsSb heterostructures with isotype heterojunctions, in which the quantum efficiency of emission is increased due to the additional production of electron-hole pairs as a result of the impact ionization that takes place near the heterointerface. The impact ionization in such heterostructures is possible due to the presence of deep wells in the energy band structure.

The photoluminescence (PL) of HgCdTe films grown by molecular beam epitaxy (MBE) has been studied in the 1.5–1.8 μm wavelength range. The post-growth annealing of samples for 20 h at 270°C in an inert atmosphere leads to changes in the spectrum and intensity of luminescence. The spectral changes are related to an increasing homogeneity of the film composition in depth as a result of the mutual diffusion of alloy components. An increase in the room-temperature PL intensity is due to the improved structure of annealed films.