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We present the results of structural characterization of Cd1 � xMnxGeAs2 chalcopyrite-type crystals with low Mn content x varying from 0 to 0.037. High resolution X-ray powder diffraction method of measurements and Rietveld refinements procedure used for analysis of obtained diffraction patterns revealed high crystal quality of the samples. The substitutional alloying of Cd1 � xMnxGeAs2, with Mn ions at Cd sites, has been confirmed. The analytical equations describing the linear reduction of the lattice parameters with increase of Mn content were deduced and compared with the literature results of theoretically estimated lattice parameters of compounds of the same kind. Copyright © 2015 John Wiley & Sons, Ltd.

Gallium nitride is studied at ambient and nonambient temperatures by powder X-ray diffraction followed by Rietveld refinement of the structure. The structure is reported for the ambient temperature on the basis of laboratory data. The diffraction data collected using a synchrotron beam serve for derivation of the lattice parameter and thermal expansion dependencies on temperature. The variation of unit-cell size on temperature was studied in detail in a broad range 11 K

Atomic layer deposition (ALD) was used to fabricate transparent and conductive thin films of ZnO. Two hundred-nano metre thick ZnO films were deposited on glass substrates at low growth temperatures varied between 120 and 240 °C. As zinc and oxygen precursors we used diethylzinc (DEZn) and deionized water, respectively. To find optimal film parameters, the structure, surface morphology, optical and electrical measurements were carried on. The films obtained at 200 °C show the highest carrier concentration (~10 20 cm -3 ) and the lowest resistivity (2 x 10 -3 Ω cm). The films exhibit mobilities up to 37 cm 2 /Vs that we associate to the process technology used. An important point of our approach was that the films studied were not intentionally doped (with Al or other group III elements) but the high electrical conductivity was achieved by playing with the sample stoichiometry and growth conditions.

Lattice absorption of Zn 1-x-y Be x Mg, Se and Cd 1-x-y Be x Zn y Se mixed crystals grown by a high pressure Bridgman method has been investigated by infrared spectroscopic ellipsometry in the wave number range from 230 cm to 5000 cm -1 . Ellip-sometric spectra of Cd 1-x-y Be x Zn y Se crystals display features in the spectral range 350-550 cm associated with BeSe-type phonon modes. In the optical spectra of Zn 1-x-y Be x Mg y Se crystals both BeSe-type and MgSe-type: lattice absorption bands are detected. The MgSe-like modes are located at approximately 300 cm -1 . The frequencies and oscillator strengths of optical phonon modes depend strongly on the alloy composition.

Extensive studies of physical properties and growth process of ZnO crystals are motivated by unique electrical and optical properties of this material. In the present work, the defect-structure characteristics of a bulk zinc oxide crystal grown by Contactless Chemical-Vapour-Transport method are studied. The macromosaic spread is found to be of the order of 1°. The values of lattice parameters and axial ratio in the main part of the crystal perfectly agree with literature data. Changes of the colour observed along the crystal correlates with intentional vapour pressure variation during the growth.

A detailed optical characterization of three wurtzite-type Cd1–x–yBexZnySe mixed crystals has been carried out by using contactless electroreflectance (CER) and photoreflectance (PR) in the temperature range of 15 to 400 K. The samples were grown by the modified high pressure Bridgman method. The transition energies of the A, B and C features of Cd1–x–yBexZnySe are determined via a lineshape fit to the CER and PR spectra. The parameters that describe the temperature dependence of the interband transition energies of the features A and C are evaluated and discussed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Zinc oxide crystals were grown by Chemical Vapour Transport using Contactless Crystal Growth technique. To apply powdered source material and long ampoules, modified temperature field was applied. 2.5 cm diameter crystals were obtained. The largest grains yielded 0.5 cm2 single crystalline substrates. The FWHM of the rocking curve was usually exceeding 60 arcsec, but areas with FWHM as low as 29 arcsec were also found. The electrical p-type conductivity of As-doped crystal was identified as increased arsenic content grain surface effect. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report on depression of superconducting transition temperature of YBa2Cu3O7 (YBCO) layers, when their thickness is reduced in proximity to ferromagnetic insulating La0.885Sr0.115MnO3 (FI-LSMO) layers in [FI-LSMO*8 u.c./YBCO*n u.c.]16 superlattices, where n = 1, 2, 4 and 6 unit cells (u.c.). The thickness of manganite FI-LSMO layers is kept at 8 unit cells. Signature of antiparallel alignment between FI-LSMO layers across YBCO spacer layers was observed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Cd1-xBexSe and Cd1-xMgxSe solid solutions were grown from the melt by the high pressure Bridgman method. Optical, luminescence and photothermal properties of these materials were investigated. Spectroscopic ellipsometry was applied for determination of the spectral dependence of the complex dielectric function (E) and refractive index n(E) at room temperature in the photon energy range 0.75-6.5 eV for samples with optic axis (c-axis) perpendicular to the air-sample interface. The critical point (CP) parameters for E0 and E1 transitions were determined using a standard excitonic CP function to fit the numerically calculated differential spectra ∂2e2/∂E2. The dispersion of the refractive index of the alloys was modelled using a Sellmeier-type relation. The values of fundamental and exciton band-gap energies were estimated from the ellipsometric and photoluminescence measurements. The origin of luminescence in Cd1-xBexSe and Cd1-xMgxSe was discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Atomic layer epitaxy (ALE) was applied to grow thin films of monocrystalline and polycrystalline ZnO. Monocrystalline films were obtained only for GaN/Al2O3 substrates, whereas use of sapphire, silicon or soda lime glass resulted in either 3D growth mode or in polycrystalline films showing preferential orientation along the c axis. Successful Mn doping of ZnO films is reported, when using organic Mn precursors. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Optical and luminescence properties of Cd0.925Be0.075Se crystal grown by the modified Bridgman method are reported. Ellipsometric spectra were measured in the photon energy range 0.75–6.5 eV for a high symmetry orientation of the optic axis (c axis) being perpendicular to the air–substrate interface. The structure in the complex dielectric function was identified as E0(A), E0(C), E1(A), E1(B), E1(C), and E2 threshold energies. A large bowing of the main energy gap was estimated. Luminescence spectra were measured in the temperature range from 38 K to room temperature. Exciton emission at room temperature has a maximum at 1.873 eV. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Magnetisation and EPR investigations were performed in mixed Zn 1-x-y Be x Mn y Se crystals. For crystals containing about 3% of Mn the transition from paramagnetic to antiferromagnetic behaviour is observed with temperature decreasing from 300 to 12 K. EPR spectra of all samples show the g-factor value in the range of 2.0065-2.0220. If Mn atoms are not introduced to the lattice, the EPR signal shows only g = 1.999.

The zinc blende (metastable) modification of mercury sulphide was stabilized by the partial substitution of Hg atoms by Mn, Fe, and Co. The structure of such crystals grown by the modified Bridgman method was investigated by X-ray diffraction and electron transmission spectroscopy techniques. The single-phase character of the crystals was demonstrated, the presence of defects resulting from the disorder in the stacking sequence of (111) layers was evidenced.

Bulk Zn 1-x Be x Te crystals were grown in the range extending up to x = 0.12. Their structural, optical and photothermal properties were characterised using X-ray diffraction, photoluminescence (PL) and photoacoustic (PA) methods. The lattice constants are found to follow a linear dependence on x. Energy gap and thermal diffusivity were determined from photoacoustic spectra. The energy-gap increasing trend with rising beryllium content is in agreement with that reported for thin (Zn,Be)Te layers on InP substrate.

Observations of Raman scattering associated with vibrational modes in Zn 1-x Mg x Se and Zn 1-x Be x Se semiconducting mixed crystals are reported. Measurements were made at room temperature for Zn 1-x Mg x Se crystals with Mg content in the range 0 < x < 0.43 and Zn 1-x Be x Se crystals with Be content in the range 0 < x < 0.41. From the polarized Raman spectra the longitudinal optical (LO) and transverse optical (TO) modes which corresponding to ZnSe-, MgSe- and BeSe-like single crystals are distinguished. Theoretical calculations of the frequencies of the ZnSe- and BeSe-like modes were also performed using modified random element isodisplacement (MREI) model. The optical modes of Zn 1-x Be x Se are compared with those of Zn 1-x Mg x Se.

Results of measurements of the GaAs, GaAs1−xPx, and GaP lattice constants in the range 300 to 700 K are presented. The resulting values of the thermal expansion coefficient and their temperature changes are discussed.

A method of growing large oriented metal single crystal plates is presented. Crystal plates without any mechanical treatment are suitable for neutron diffraction work. The mosaic spread of these crystals is smaller than that of cylindrical single crystals. Es wird eine Zuchtungsmethode fur grose orientierte metallische Einkristallplatten vorgestellt. Einkristalle ohne mechanische Bearbeitung eignen sich besonders fur Neutronendiffraktometrische Untersuchungen. Die Mosaikblockverkippung in Einkristallplatten wurde kleiner als die in zylindrischen Einkristallen gefunden.