The purpose of this work was to study the features of cathodoluminescence, the impurity content, and the charge carrier diffusion length in various growth sectors of a single crystal diamond grown by the HPHT method using a BaCO3-enriched precursor as a typical chemical form of the radioactive isotope carbon-14. It is shown that the addition of BaCO3 does not lead to significant changes in the optical properties of the obtained synthetic diamonds, although the distribution of nitrogen and boron impurities in the {111} and {100} growth sectors is different. It is shown that the impurity content affects the cathodoluminescent (CL) properties of diamond growth sectors and the charge carrier dissipation length. It has been observed that the shape of the CL bands, their intensity, and the decay time depend on the impurity content. In addition, it has been demonstrated that an increase in boron content enhances the luminescence intensity by an order of magnitude. At the same time, the boron impurity causes blue coloring of the diamond matrix, which is related to absorption of CL. The results obtained can be used to optimize the synthesis of self-glowing radioactive diamonds activated with boron and carbon-14.

An Erratum to this paper has been published: https://doi.org/10.1134/S0016702925190036

In this work, bulk β-Ga2O3 crystals were grown by the Czochralski method and doped with iron with different amounts of dopants. The dependence of the crystalline quality on the Fe content was studied. Measurements of the specific resistance and optical transmission spectra confirmed the compensation of donors, the binding of conduction electrons, and the growth of the specific resistance with an increase in the iron content in the crystals up to 1.6 × 1011 Ω cm. The obtained value of the activation energy of the deep level of Fe was EA = 0.66 eV.

Halogens play an essential role in mantle petrology, but no data on halogen content in diamonds are available to date. Concentrations of fluorine and chlorine in diamond were determined quantitative for the first time, using quantitative SIMS analysis based on external standards prepared by the ion-implantation of halogens. Fluorine concentrations in diamond vary from 0.018 to 0.036 at ppm (3.2‒6.3 × 1015 at/cm3); chlorine concentrations are similar, from 0.014 to 0.034 at ppm (2.4‒4.5 × 1015 at/cm3). Most likely, F and Cl are related to microinclusions in diamonds, although one cannot exclude their position in the diamond lattice. The source of halogens in the studied diamonds is complex. A part of F and Cl is juvenile, remained from their primary concentrations. Another part, forming the halogen repository in the deep Earth, comes to the mantle via subduction. Fluorine may form the fluorine–vacancy (F–V) complex in the diamond structure, F and Cl may be compositional parts of microinclusions in diamonds as well. The F/Cl ratio in the studied diamonds (1.00–1.82) is similar to F/Cl ratios in kimberlites (0.38‒1.68). It differs from the estimates for the Earth’s mantle (0.62–0.68) but is close to enstatite chondrite values (1.16–2.77).

The possibility of manufacturing photovoltaic converter structures due to solid-phase reactions of substitution of Sb atoms in GaSb semiconductor wafers with As or P atoms, with simultaneous diffusion of Zn, is demonstrated.

A set of ten diamonds from different sources representing the main types of physical classification (IaA, IaAB, IaB and IIa) has been first explored by FTIR spectroscopy and SIMS calibrated by hydrogen ion implantation. The concentrations of hydrogen in the studied diamonds measured by SIMS range between 9.98 and 47.6 at.ppm or from 1.76 × 1018 to 8.40 × 1018 at./cm3. The 3107 cm−1 absorption line has been detected by FTIR spectroscopy (resolution near 1 cm−1) in five studied diamonds (IaB and IaAB). The 3107 cm−1 IR absorption lines due to H defects in these diamonds have been successfully described by the Lorentzian shape and their parameters have been evaluated. Based on the linear regression equation relating intensities of the 3107 cm−1 IR absorption lines in the studied diamonds with their H defect concentrations, the H defect IR absorption at 3107 cm−1 in diamond has been quantified. The absorption calibration constant for diamond's 3107 cm−1 absorption line is 386 ± 64 ppb cm2. The corresponding cross-section per one H defect σ3107 (cm2) = (9.34 ± 1.25) × 10−18 /Γ (cm−1), Γ is the full width at half maximum (FWHM) of the 3107 cm−1 absorption line. Based on a widely accepted interpretation that the H defect resulting in the 3107 cm−1 IR absorption peak in diamonds is the N3VH defect, the values of the obtained calibration constant and cross-section have been assigned to the N3VH defect in diamond. The equations relating concentration of the N3VH defect ([N3VH]) with the 3107 cm−1 IR absorption line integrated intensity (I3107) and intensity (α3107) are as follows: [N3VH] (ppb) = (386 ± 64) I3107; [N3VH] (ppm) = (0.607 ± 0.080) α 3107 (cm−1)Γ (cm−1). Hydrogen impurities that do not contribute to the IR absorption at the 3107 cm−1 peak were detected in all studied diamonds.

Thick smoothly graded Al x Ga 1−x As layers (50–100 µm) are used in light-emitting diode structures and also for creation of high-power photovoltaic converters with side-input of laser radiation. To achieve the required thickness of the Al x Ga 1−x As layer the high temperature LPE growth technique is required. However high epitaxial temperature increases the unintentional doping level. Epitaxy from mixed Ga-Bi melts was investigated as a way to solve this problem. It was found that for growing relatively thick Al x Ga 1−x As layers, it is expedient to use Ga-Bi melts with 20 at.% or less bismuth content. SIMS and Hall characterization of Al x Ga 1−x As layers revealed that the growth of Al x Ga 1−x As from mixed Ga-Bi melts reduces the background doping level (including carbon) and influences the native defect formation keeping the n-type conductivity. This effect is explained by the changes of the group III and V elements concentrations in the melt as well as Bi incorporation in the lattice.

The results of a study of nitrogen-containing active regions based on superlattices grown on GaAs substrates are presented. Active regions based on alternating InAs and GaAsN layers were fabricated by molecular-beam epitaxy using a nitrogen plasma source. Based on the XRD analysis, the thicknesses and average composition of superlattice layers are estimated. The study of dark-field images obtained by transmission electron microscopy showed the presence of interdiffusion of InAs into GaAsN. The results of a study of the photoluminescence and electroluminescence spectra at different pump levels are presented. Efficient electroluminescence is demonstrated near 1150 nm with a full width at half-maximum of about ~90 meV. Keywords: Superlattices, molecular beam epitaxy, gallium arsenide, dilute nitride, GaAsN, InAs.

For the first time a self-glowing blue-colored single crystal diamond (weighing 0.14 g) was synthesized by method of temperature gradient at high-pressure and high-temperature (TG HPHT) using starting precursor activated with carbon-14 in the form of BaCO3. The total content of 14C in the crystal matrix is estimated 0.008 wt.% or 1.8 MBq in total. The diamond emits intrinsic radioluminescence, which is visually observed in the dark. Basic properties of this diamond are discussed.

Thick smoothly graded AlxGa1−xAs layers (50–100 µm) are used in light-emitting diode structures and also for creation of high-power photovoltaic converters with side-input of laser radiation. To achieve the required thickness of the AlxGa1−xAs layer the high temperature LPE growth technique is required. However high epitaxial temperature increases the unintentional doping level. Epitaxy from mixed Ga–Bi melts was investigated as a way to solve this problem. It was found that for growing relatively thick AlxGa1−xAs layers, it is expedient to use Ga–Bi melts with 20 at% or less bismuth content. SIMS and Hall characterization of AlxGa1−xAs layers revealed that the growth of AlxGa1−xAs from mixed Ga-Bi melts reduces the background doping level (including carbon) and influences the native defect formation keeping the n-type conductivity. This effect is explained by the changes of the group III and V elements concentrations in the melt as well as Bi incorporation in the lattice.

The results of characterization of the quantum cascade heterostructure laser based on AlInAs/GaInAs system emitting at a wavelength of 5 microns are presented. The use of dynamic secondary ion mass spectrometry for analyzing modern semiconductor heterostructures has been shown to be effective in determining the concentrations of both basic and impurity elements in nanoscale layers.

The possibility of controlling the composition of lateral nanowires by the method of growth under quasi-equilibrium conditions in a quasi-closed volume from indium, phosphorus, and arsenic vapors with Au catalyst in the “vapor-liquid-solid” mechanism has been demonstrated for the first time. It has been experimentally shown that the additional presence of arsenic in the indium-phosphorus source leads to the coalescence of catalytic gold droplets at the initial stage of the growth, which determines the further morphology and growth kinetics of nanostructures. An additional formation of indium phosphide nanostructures with a composition different from that of the main nanowires was found. The results of the studies expand the possibilities of the developed method for obtaining lateral nanowires on gallium arsenide substrates.

The current-voltage characteristics of two types of GaAs-(delta Si)/i-(GaAs/Al0.2Ga 0.8As)/p++-Al0.2Ga0.8As-(delta Be) tunnel diode (TD) structures grown at different temperatures and epitaxial layer thicknesses have been investigated in the temperature range 100-400 K. Temperature dependences of the main TD parameters were determined: the peak value of the tunnel current density (Jp), the valley current density (Jv) and the differential resistance (Rd). TD samples of structure A grown at 500 degrees C exhibited the highest values of the peak current density (Jp <= 220 A/cm2) with temperature stability of 93 % over the whole temperature range. TD samples of structure B grown at 450 degrees C showed lower values of the peak tunneling current density (Jp <= 150 A/cm2), with significantly linear temperature dependence. Our findings can be used in the design and development of monolithic multijunction photoconverters of powerful laser radiation.

Samples of heterostructures made on the basis of semiconductor wafers of binary compounds GaAs, GaSb and InAs as a result of substitution of Group V elements of atoms by atoms of other Group V elements supplied in the form of vapors, including simultaneous Zn diffusion are studied. The possibility of using the obtained structures to make a photoelectric converter is demonstrated.

The question of why a high-quality bulk AlN crystal can be grown on a SiC seed, which is superior in a number of parameters to the same crystal grown on its own seed, remains open. We set ourselves the task of comprehensive analysis of the process of the formation of bulk AlN crystals on SiC using Raman spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy (EDXS), secondary ion mass spectroscopy (SIMS), and optical microscopy. We managed to detect silicon on the surface of the grown AlN сrystals and traces of silicon at the SiC/AlN phase boundary. In connection with this discovery, we consider a new model for the formation of high-quality bulk AlN crystal growth on SiC substrates through the formation of a layer of liquid silicon. The application of this model will facilitate the growth of large, high-quality AlN crystals.

The origns leading to the appearance of a green color of AlN crystals grown by sublimation on SiC seeds are investigated. It was shown by the method of secondary ion mass spectroscopy that the color of crystals weakly depends on the content of silicon and carbon, and a green or dark color appears only with an increased content of carbon in comparison with silicon. The presence of a separate amorphous carbon phase in these crystals was established by the method of Raman light scattering. The separation of the carbon phase in the process of crystal growth makes it difficult to obtain high-quality AlN crystals, as well as AlN-SiC solid solutions. The influence of growth conditions on the optical properties of AlN crystals is analyzed.

Abstract A set of natural diamonds, representing the main types of physical classification (IaA, IaAB, IaB and IIa), was studied with the utilisation of FTIR and SIMS with the implantation of hydrogen into a standard sample. The volumetric concentrations of hydrogen in the studied diamonds are between 5-24 at.ppm. According to their FTIR spectra, the diamonds form two groups: low-hydrogen (0.07‒1.33 cm-1 arbitrary units) and hydrogen-rich (8.4‒15.2 cm-1 arbitrary units) diamonds. The volumetric concentrations of hydrogen, established with the use of SIMS correspond to the FTIR data: low-hydrogen diamonds have 5‒11 at.ppm of hydrogen, and hydrogen-rich diamonds have 13-24 at.ppm of hydrogen. There is a correlation between SIMS and FTIR determinations of hydrogen concentrations in diamonds. Each group is characterised by its trend. The correlation between volumetric hydrogen concentration and FTIR characteristics for low-hydrogen diamonds is expressed by the equations: [H]at.ppm = 10.71*[H]IR + 3.79 and for high-hydrogen diamonds and [H]at.ppm = 1.57*[H]IR-0.3. Our observations confirm bonding hydrogen with nitrogen in H-rich diamonds. Another structure may be suggested for the hydrogen impurity in low-H diamonds. It is also possible that the instrumentally determined hydrogen concentrations in diamond reflect IR-active and other hydrogen centres.

The structural properties and crystal quality of AlxGa1 ‒ xN/AlN/Al2O3 heterostructures grown by ammonia-assisted molecular-beam epitaxy with a high silicon concentration in the AlxGa1 ‒ xN:Si layers are studied by atomic force microscopy and dynamic secondary-ion mass spectrometry. It is shown that if AlN buffer layers of metal polarity contain inversion domains of nitrogen polarity, during subsequent growth of the AlxGa1 ‒ xN:Si layers, inversion domains do not grow to the surface, but change their nitrogen polarity for metal polarity. At the place of AlN inversion domains, broadening AlxGa1 ‒ xN columns of metal polarity grow, which coalesce in a homogeneous film with the Me-polar matrix surrounding them. The thickness corresponding to complete intergrowth increases with the Al content in the layers.

A new method for growth of Au-catalyzed lateral Ga(In)AsP nanostructures in a quasi-closed volume from a vapor source under semi-equilibrium conditions has been studied. Varied time-temperature conditions and nucleation modes were examined. It was found that lateral nanostructures elongated in the [1 (1) over bar0] direction are formed on a (100) GaAs substrate at about 500 degrees C. Raising the growth temperature is accompanied by a significant change of the morphology of the nanostructures. The modified surface has a random textured structure with predominant pyramidal faceting. Changes in the alloy composition of the nanostructures were studied.

Characteristics of double-cascade nonmonolithic p-i-n AlGaAs/GaAs photovoltaic converters of high-power laser radiation, electrically combined with n++-GaAs/i-GaAs/i-AlGaAs/p++-AlGaAs tunnel diodes, have been studied. The AlGaAs/GaAs p-i-n structures of the photovoltaic converters and n++-GaAs/i-GaAs/i-AlGaAs/p++-AlGaAs tunnel diodes were grown by molecular-beam epitaxy. The photoelectric characteristics of the double-cascade AlGaAs/GaAs photovoltaic converters were examined in the temperature range from 103 to 298 K under excitation with a laser light wavelength of 809 nm and a power density ⩽92 W/cm2. The double-cascade p-i-n AlGaAs/GaAs nonmonolithic photovoltaic converters of planar design had a fill factor of 0.88 and efficiency of 58.2% at a temperature of 103 K. It was shown experimentally that the current-voltage characteristics of the connecting n++-GaAs/i-GaAs/i-AlGaAs/p++-AlGaAs tunnel diodes affect the photoelectric parameters of the double-cascade photovoltaic converters of high-power laser light.