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1
100%
EN
The structural properties of MBE grown YbTe layers were investigated by X-ray diffraction methods and photoluminescence measurements. YbTe films were grown on the ZnTe and CdTe buffer layers crystallised on the GaAs(100) 2° off oriented substrates and on the BaF_{2}(100) substrates. In the case of GaAs substrates the two-dimensional growth mode of YbTe was observed on reflection high energy electron diffraction picture. Results of the X-ray rocking curve and photoluminescence excitation measurements indicate that the structural properties of YbTe films are comparable to the properties of the MBE grown ZnTe and CdTe layers on the GaAs(100) substrates. The measured values of the YbTe lattice constant parallel and perpendicular to the growth plane show that the 1 μm thick layers are partially strained. The full width at half maximum values of the X-ray rocking curves are the smallest (900 arc seconds) for the YbTe films crystallised on the 2 μm thick CdTe bucher layer grown on the GaAs(100) substrate. In the case of BaF_{2}(111) substrate the two-dimensional MBE growth mode of YbTe was not observed.
EN
High pressure - high temperature experiments for MnTe of NiAs type were performed using a synchrotron radiation as X-ray source and a cubic anvil X-ray diffraction press to produce nonambient sample environment. In the investigated range of pressure (0-67.5 kbar) on uploading and with following temperature rise from 296 to 1273 K (at 67.5 kbar), the structure type of MnTe is conserved. An earlier reported nonlinear behaviour of lattice-parameter c_{0} is not found in the present study. Possible reasons of this discrepancy are discussed. The value of bulk modulus and its pressure derivative were calculated from the pressure-volume dependence by fitting the Birch-Murnaghan equation.
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Solubility Limit of Ni in Cd_{1-x}Ni_{x}Te Crystals

100%
EN
The Cd_{1-x}Ni_{x}Te crystals were grown by the Bridgman method. The investigated samples were cut from five different ingots with nominal contents of nickel varied from 0.005 to 0.05. The investigations were performed using X-ray powder diffraction method and energy dispersive and wavelength dispersive electron microprobe analysis. The samples were ałso examined in a scanning electron microscope. Examinations of wavelength dispersive electron microprobe analysis show that the actual contents of nickel differ from the nominal values. The solubility limit of nickel was determined to be x = 0.005. The precipitates of NiTe were found in samples of a greater content of nickel. Their dimensions were between 5 to 90 micrometers. X-ray powder diffraction measurements did not reveal any significant change of the lattice constant of investigated crystals in comparison with pure CdTe.
4
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X-Ray Study of Synthetic Alunite

100%
EN
Synthetic alunite was obtained by two different synthesis methods. Powder data obtained with a standard Bragg-Brentano geometry of two analyzed samples are reported for a broad angular range. The chemical analysis as well as the unit-cell dimensions indicate that the analyzed alunite is K and Al deficient and contains excess water. A need for high resolution diffraction experiments is expressed.
EN
Electron probe microanalysis and X-ray diffraction studies have been performed on samples of ternary Cd_{1-x}Mg_{x}Te (0.05 ≤ x ≤ 0.09) and quaternary Cd_{1-x-y}Mg_{x}Mn_{y}Te (0.025 ≤ x ≤ 0.4; 0.025 ≤ y ≤ 0.7) alloys. The investigated samples were cut from 24 different ingots grown by Bridgman method. Microprobe examinations have revealed significant differences between actual and nominal content of Mg along the longitudinal direction for both ternary and quaternary ingots. In contrast to Mg, for most Cd_{1-x-y}Mg_{x}Mn_{y}Te samples the actual Mn content was within ±5% of nominal content. The lattice constants have been determined by X-ray powder diffraction method. Whereas Cd_{1-x-y}Mg_{x}Mn_{y}Te samples exhibit only zinc blende crystal structure for the entire region of x and y investigated, the Cd_{1-x}Mg_{x}Te alloy has two different structures depending on Mg content; a zinc blende structure below x = 0.5 and a wurtzite structure above it. In both alloys the lattice constant decreases with increasing Mg content.
6
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High-Pressure Diffraction Study of Ga_{1-x}Al_{x}As

88%
EN
The Ga_{1-x}Al_{x}As sample of x=0.5 was prepared from a high quality single crystal grown by electroepitaxy on GaAs. The high-pressure diffraction experiments were performed using a diamond anvil cell and a germanium solid state detector. The zinc-blende phase is stable up to about 17.5 GPa on uploading. A high-pressure phase manifests itself at about 17 GPa, a complete phase change occurs at 18.7 GPa. On downloading, the zinc-blende phase reappears at about 10 GPa. The powder pattern of the high-pressure phase shows some similarities with the GaAs high pressure phases.
EN
The nanocrystalline state of the formally amorphous alloy Fe_{73.5}Cu_{1}Nb_{3}Si_{15.5}B_{7} is achieved by a heat treatment at temperatures between 500°C and 600°C. The XANES and EXAFS methods were applied for investigation of local structure and chemical bonding around Fe atoms in amorphous and nanocrystalline alloys. The Fe K absorption spectra were measured in the transmission mode at room temperature for Fe_{73.5}Cu_{1}Nb_{3}Si_{15.5}B_{7} amorphous and nanocrystalline alloys and compared with the spectra for Fe metallic foil and Fe_{3}Si polycrystalline samples.
EN
Ar-O-Zn plasma discharges created during DC reactive magnetron sputtering of a Zn target and RF reactive magnetron sputtering of a ceramic ZnO target were investigated and compared by means of the Langmuir probe measurements in order to determine the mechanism of growth of porous Zn films during DC-mode Zn reactive sputtering. The power supplied to the magnetrons during the sputtering was kept at 125 W and the plasma was characterised as a function of oxygen content in the sputtering gas mixture, ranging from 0 to 60% for two gas pressures related to porous Zn film deposition, namely 3 mTorr and 5 mTorr. Based on the correlation of plasma properties measurements with scanning electron microscope imaging and X-ray diffraction of the films deposited under selected conditions it was found that the growth of porous, polycrystalline Zn films was governed by high electron density in the plasma combined with a high electron temperature and an increased energy of the ions impinging on the substrate.
9
88%
EN
The effects of interaction between thin films of Zn and (100)InP were studied with secondary ion mass spectrometry, X-ray diffraction and trans­mission electron microscopy. Zn was found to penetrate the native oxide on InP surface during deposition and to form an ohmic contact when deposited on highly doped n-type InP. Heat treatment causes the formation of Zn_{3}P_{2} phase lattice matched to InP.
EN
The aim of the present paper is to study the possibility of application of the X-ray quasi-forbidden reflection method to the composition determination of the sphalerite-type Cd_{1-x}M_{x}Te = Mg, Zn, Mn) single crystals. The method is based on the property of quasi-forbidden reflections that their integral intensity is very sensitive to composition and weakly sensitive to crystal lattice defects. An example of application for a Cd_{1-x}Mn_{x}Te single crystal is presented.
EN
Structural properties of ZnTe, MnTe, and Mn_{1-x}Zn_xTe alloy with zinc-blende, NiAs, and wurtzite phases were investigated by ab initio calculations. The calculated structural properties are in good agreement with the available experimental data. Theory predicts that the zinc-blende phase is more stable than wurtzite for all compositions. Mn_{1-x}Zn_xTe samples with 0.01 < x < 0.20 were grown by MBE. X-ray analysis of their crystalline structure revealed the presence of zinc-blende, wurtzite, and NiAs phases. The dominant phase changes from NiAs for the sample with x=0.01 to wurtzite for x=0.20. The observed stabilization of the wurtzite phase is possibly due to the hexagonal structure of the MnTe buffer.
EN
We report on preparation and electrical characterization of the epitaxial BaTiO₃ (BTO), BiFeO₃ (BFO) thin films and BFO/BTO bi- and multilayers, grown on (001) SrTiO₃ (STO) and (LaAlO₃)_{0.3}(Sr₂TaAlO₆)_{0.7} (LSAT) substrates. The ferroelectric properties were characterized using the electric force microscopy method to image and switch the electric domains. This fabrication process opens the routes towards wide study of magnetoelectric effect in complex oxide heterostructures.
EN
Single crystals of Cd_{1-x}Co_xTe and Cd_{1-x-y}Co_xMn_yTe are characterized with X-ray powder diffraction and electron microprobe to establish compositional dependence of the lattice parameters and deduce Co solubility limit. The experimental compositional profiles are examined on specimens taken from various locations of ingots along their longitudinal axes and compared with normal freezing distributions. The values of Co segregation coefficient are analyzed for both ternary and quaternary alloys in terms of normal freezing mode.
EN
We report on growth by molecular beam epitaxy of cubic MnTe(111) layers on BaF_{2} (111) substrates. Layers as thick as 0.2-1.0 μm were grown. Basic characterization by X-ray diffraction shows that the cubic crystal structure is deformed to orthorhombic symmetry.
EN
Phonon excitations in (CdTe)_{12}/(MnTe)_{n} (100) superlattices (n=2, 4, 8) were investigated at 295 K and 25 K with the use of Raman scattering. From the "folded" phonon frequencies the elastic constant c_{11} value for MnTe was estimated. The strain arising from lattice mismatch (determined by X-ray diffraction) results in shifts of MnTe and CdTe "confined" LO phonon frequencies. For the precise determination of LO phonon dispersions an additional shift due to Mn diffusion at the CdTe/MnTe interface should be taken into account.
EN
Single crystals of Cd_{1-x}Ni_{x}Se alloys (x ranging from 0 to 0.075) were investigated using electron microprobe and X-ray diffraction. The analysis shows the presence of Ni-Se precipitates. The solubility limit of Ni is estimated to be 0.008.
EN
In this paper we discuss a possibility of an optical characterization of thin semiconductor epilayers by Raman scattering measurements. As an example zinc blende Cd_{1-x}Mn_{x}Te epilayers (0.66 ≤ x ≤ 1.0) have been grown by molecular beam epitaxy method and investigated by Raman scattering and X-ray diffraction. Information resulting from both methods is compared and discussed.
18
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Elastic Constants of β-HgS

76%
EN
The elastic constants of single crystals of β-HgS highly doped with iron were directly determined at room temperature from the measurements of ultrasonic wave velocities by the pulse-echo technique. The values of c_{11}=6.750, c_{12}=5.186, and c_{44}=2.42 (given at 10^{10} N m^{-2} units) were obtained and compared with the experimental data taken for other mercury chalcogenides. The elastic characteristics of this group of materials is quite similar to those of Cd and Zn chalcogenides.
EN
In-Ga-Zn-O thin films were fabricated by means of reactive RF magnetron sputtering. Mechanism of free electrons generation via oxygen vacancies formation is proposed to determine the relationship between oxygen content in the deposition atmosphere and the transport properties of IGZO thin films. The depletion-mode a-IGZO thin film transistor with field-effect mobility of 12 cm^2/(Vs) has been demonstrated.
EN
In this communication we report successful growth of monocrystalline cubic ZnS and monocrystalline and polycrystalline cubic and wurtzite films of CdS by atomic layer epitaxy. Structural and optical properties of these films are analysed. ZnS (and CdS/ZnS) films grown on GaAs substrate are cubic. Atomic layer epitaxy grown films provide several advantages over ZnS and CdS materials grown by other techniques, especially compared to bulk material, which is grown at higher temperatures. First results for ZnS/CdS/ZnS quantum well structures are also discussed.
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