Crystal Research and Technology

Cover image for Vol. 49 Issue 10

Early View (Online Version of Record published before inclusion in an issue)

Editor: Wolfgang Neumann (Editor-in-Chief), Klaus-W. Benz (Consulting Editor)

Online ISSN: 1521-4079

Associated Title(s): physica status solidi (a), physica status solidi (b), physica status solidi (RRL) - Rapid Research Letters

VIEW

  1. 1 - 20
  1. Original Papers

    1. Controlled synthesis of barium chromate microcrystals

      H. Xiao, S.S. Ding, X. Xu, N. Pan, D.Y. Fan, H.J. Yang, M. Lei, Y.X. Du, R. Zhang, Y.G. Wang and W.H. Tang

      Article first published online: 21 OCT 2014 | DOI: 10.1002/crat.201400267

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      BaCrO4 microcrystals with various morphologies were synthesized using poly (sodium 4-styrenesulfonate) (PSSS) as template agent. It is found that pH values and concentrations of reactants and PSS are important parameters in the morphology and size evolution of BaCrO4. PSS can complexes Ba2+ first, then affects the nucleation and crystallization process by interacting with the face of crystal. In addition, the possible mechanism of photoluminescence (PL) spectra was also proposed.

    2. Fast growth of thin multi-crystalline silicon ribbons by the RST method

      Bertrand Heilbronn, Fabrice De Moro, Emilie Jolivet, Elsa Tupin, Benjamin Chau, Romain Varrot, Béatrice Drevet, Séverine Bailly, Delphine Rey, Hélène Lignier, Yinghao Xi, Thècle Riberi-Béridot, Nathalie Mangelinck-Noël, Guillaume Reinhart and Gabrielle Regula

      Article first published online: 13 OCT 2014 | DOI: 10.1002/crat.201400213

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      The RST process is a ribbon direct-wafering technology with specific ability for thin multi-crystalline wafer production. Efficiency over 16% has been reached. Impurities, such as C and transition metals, need to be eliminated in the process. A model is proposed which shows that the carbon substrate is an important source of carbon contamination in the silicon melt. Experimental segregation studies conclude to a near-diffusive regime.

    3. Synthesis, characterization, and tribological properties of two-dimensional Ti3C2

      Jin Yang, Beibei Chen, Haojie Song, Hua Tang and Changsheng Li

      Article first published online: 13 OCT 2014 | DOI: 10.1002/crat.201400268

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      We describe a simple and convenient approach to fabricate 2D-layered Ti3C2 by the HF exfoliation of laminated Ti3AlC2. The exfoliated Ti3C2 was quite thin and exhibited individual layer or stack of several layers, and can greatly enhance the friction-reducing and anti-friction properties of base oil. This study is helpful in designing new 2D-layered lubricating materials capable of meeting emerging needs in practical applications.

    4. Fabrication of hollow ZnO nanostructures by a CTAB-assisted chemical bath deposition method

      Ying Hou and Ming Yang

      Article first published online: 8 OCT 2014 | DOI: 10.1002/crat.201400231

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      Different ZnO hollow nanostructures can be synthesized by a simple chemical bath deposition method showing tunable optical properties.

    5. Texture gradient studies of a Cu-tube by the robot at STRESS-SPEC

      N. Al-hamdany, H.-G. Brokmeier, C. Randau, W. M. Gan and M. Völler

      Article first published online: 7 OCT 2014 | DOI: 10.1002/crat.201400229

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      The recrystallization components show small gradient around the circumference of 140 mm Cu tube according to the eccentricity and ovality while the deformation components are nearly constant. The robot was used to measure the pole figures automatically and non-destructive around the circumference with the use of neutrons diffraction.

    6. Twinning in GaAs nanowires on patterned GaAs(111)B

      Thomas Walther and Andrey B. Krysa

      Article first published online: 7 OCT 2014 | DOI: 10.1002/crat.201400166

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      We studied twinning in GaAs nanowires grown via holes in a silica mask deposited on GaAs(111)B substrates by metal-organic chemical vapour epitaxy without catalysts. {111} twins perpendicular to the growth direction lead to corrugation of their {110} side walls. All twins are rotational, commencing with Ga and finishing with As atoms. Energy-loss spectroscopic profiling showed no significant changes in the band-gap or plasmon energy at those twin boundaries, reflecting the small energetic changes related to twin formation.

    7. Characteristics of traps in Tl2Ga2Se3S single crystals by low-temperature thermoluminescence measurements

      S. Delice and N.M. Gasanly

      Article first published online: 3 OCT 2014 | DOI: 10.1002/crat.201400140

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      Thermoluminescence measurements in Tl2Ga2Se3S single crystals were performed using various heating rate method in the temperature range of 10−70 K. One glow curve having maximum temperature of 36 K was revealed. Application of heating rate and curve fitting methods gave compatible result with the activation energy of defect level as 13 meV. Traps distribution was also studied using various illumination temperatures method. A quasi-continuous distribution of traps states was established.

    8. Understanding the effect of solvent polarity on the habit modification of monoclinic paracetamol in terms of molecular recognition at the solvent crystal/interface

      C. Sudha and K. Srinivasan

      Article first published online: 1 OCT 2014 | DOI: 10.1002/crat.201400200

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      Bulk single crystal of paracetamol was grown from ethanolic solution for the first time. Solutions with different solvents having different chemical nature and polarity yielded paracetamol crystals with different habits: columnar and prismatic morphology from polar protic, aprotic and in non-polar solvents. Crystal faces ends up with different growth rate in context with solubility of solute, evaporation number of solvent, supersaturation rate and intermolecular interaction between solvent/crystal interface.

    9. Selective reading of stored information in RE doped aluminium perovskites

      D. Chiriu, C.M. Carbonaro, R. Corpino, L. Stagi and P.C. Ricci

      Article first published online: 25 SEP 2014 | DOI: 10.1002/crat.201400158

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      We focus on the possibility to control and use carrier traps to engineer new devices for optical memory storage by using rare earths doped aluminium perovskites . In this perspective, the optical and structural characterizations are presented and the effects of visible irradiation on the thermoluminescence measurements are discussed. Three trap levels are observed and the selective effects of red, blue and deep blue irradiation show the feasibility in the near future of new promising transparent displays.

    10. Undercooling measurement and nucleation study of silicon droplet solidification

      M.G. Tsoutsouva, T. Duffar, C. Garnier and G. Fournier

      Article first published online: 23 SEP 2014 | DOI: 10.1002/crat.201400165

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      An experimental setup has been designed and developed for the study of nucleation phenomena, where a silicon droplet is directly placed, melted and solidified on a substrate. The melting-solidification process was filmed and the undercooling temperature was measured by monochromatic and bichromatic pyrometers. It was found that the nature of the material of the substrate plays a role on the solidification process and droplet formation. The figure illustrates the macroscopic top/side views of solidified silicon droplets on fused silica and zyarock substrates.

  2. Review Articles

    1. Growth of SiC bulk crystals for application in power electronic devices – process design, 2D and 3D X-ray in situ visualization and advanced doping

      Peter Wellmann, Georg Neubauer, Lars Fahlbusch, Michael Salamon and Norman Uhlmann

      Article first published online: 19 SEP 2014 | DOI: 10.1002/crat.201400216

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      The paper reviews the physical vapor transport growth method of silicon carbide as applied today. Special emphasis is put on in situ growth monitoring tools based on 2 D and 3 D X-ray imaging that could be a tool for production monitoring. These techniques allow a precise determination of the crystal and source material evolution. Another topic will be the processing of highly conductive p-type 4 H-SiC which is of particular interest for power electronic switches.

  3. Original Papers

    1. Crystal growth of sapphire for substrates for high-brightness, light emitting diodes

      Frank J. Bruni

      Article first published online: 11 SEP 2014 | DOI: 10.1002/crat.201400230

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      Sapphire has emerged as the preferred substrate for high-brightness, light emitting diodes (HB-LEDs) made with a GaN epilayer. A wide range of processes are employed for sapphire growth. These include Czochralski, Kyropoulos, Edge-defined, Film-fed Growth, Bagdasarov, classical Bridgman and several variants of Bridgman. This paper reviews the major growth processes and notes that facet formation on curved interfaces may still be a rate-limiting issue for melt grown crystals.

    2. Effect of cesium chloride addition on crystal growth, structural, thermal and optical properties of γ-glycine single crystal

      C. Yogambal, R. Ezhil Vizhi and D. Rajan Babu

      Article first published online: 4 SEP 2014 | DOI: 10.1002/crat.201400151

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      Single crystal of γ-glycine in the presence of cesium chloride has been grown by slow evaporation method. The characteristic peak at 25.5° (2θ) corresponds to γ-glycine and the grown crystal belongs to hexagonal system. The γ-glycine single crsyal was thermally stable up to 213 °C. SHG efficiency of γ-glycine in the presence of cesium chloride was found to be 6 times greater than that of KDP and it is a promising material for NLO device fabrication.

    3. Effect of thickness on structural and optical properties of vacuum-deposited Sn2Sb2S5 thin films

      N. Khedmi, M. Ben Rabeh, D. Abdelkadher, F. Ousgi and M. Kanzari

      Article first published online: 2 SEP 2014 | DOI: 10.1002/crat.201400170

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      Sn2Sb2S5 crystal was successfully synthesized via the horizontal Bridgman method. X-ray diffraction spectra indicated that the Sn2Sb2S5 material was polycrystalline in nature having orthorhombic structure. Sn2Sb2S5 films have absorption coefficients between 104 and 105 cm-1 in the visible and NIR range and the values of band gap are in the range 1.5-1.7 eV. This demonstrates that Sn2Sb2S5 can be used as absorber in photovoltaic application.

    4. Universal approach for nonstoichiometry determination in binary chemical compounds

      Igor Avetissov, Elena Mozhevitina, Andrew Khomyakov and Tran Khanh

      Article first published online: 29 AUG 2014 | DOI: 10.1002/crat.201400201

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      A universal approach for a development of nonstoichiometry measurement technique for binary compounds has been proposed. The approach is based on pi-T-x diagram analysis for binary chemical compounds with variant mutual arrangements of stoichiometry, congruent sublimation and SLV lines. Nonstoichiometry detection limits for PbTe, CdS, CdSe, CdTe, ZnSe, ZnTe from 10−4 up to 5×10−6 mol.% with a relative accuracy <18 rel. % were found out for the different excess component.

    5. Influence of grain boundaries intentionally induced between seed plates on the defect generation in quasi-mono-crystalline silicon ingots

      Matthias Trempa, Christian Reimann, Jochen Friedrich, Georg Müller, Andreas Krause, Lamine Sylla and Thomas Richter

      Article first published online: 18 AUG 2014 | DOI: 10.1002/crat.201400226

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      Quasi-Mono silicon ingots were grown in laboratory scale by directional solidification method using various grain boundary relationships between adjacent seed plates covering the crucible bottom. In dependence on the grain boundary type the formation of crystal defects like dislocations or small angle grain boundaries above the seed gaps could be significantly reduced.

    6. A study on the effect of oxygen implants in CuInSe2 by photoacoustic spectroscopy

      Ameur Zegadi, Mustapha Rouha and Fatima Zohra Satour

      Article first published online: 12 AUG 2014 | DOI: 10.1002/crat.201400164

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      The near band edge optical properties of oxygen implanted CuInSe2 single crystals are analyzed using photoacoustic spectroscopy. The introduction of oxygen has given rise to a shallow defect level with ionization energy of 31 meV and a deep one with ionization energy of 256 meV. Some defects which have their origins in the defect VSe have either disappeared or reduced in their intensity suggesting that oxygen has filled these sites.

    7. Engineering ZnO nanowire surfaces via a chemical method

      Y. F. Zhu, D. H. Fan, G. H. Zhou and F. Gu

      Article first published online: 28 JUL 2014 | DOI: 10.1002/crat.201400162

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      Porous nanowires with large surface area are advantageous for device applications. However, the synthesis of this kind of nanostructure has rarely been reported. In this paper, quasi-aligned ZnO nanowire arrays with porous surfaces were successfully fabricated via a facile chemical method. Time-dependent experiments have also been carried out to better understand the formation process of porous structure on the nanowire surface.

    8. Present stage and future prospects of development of compressor material

      T. Kitashima, K. S. Suresh and Y. Yamabe-Mitarai

      Article first published online: 28 JUL 2014 | DOI: 10.1002/crat.201400156

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      Titanium alloys are attractive for use in the compressor of jet engines because of their high strength-to-density ratio. This study describes the development of high-temperature titanium alloys, mainly focusing on the effects of alloy composition and microstructure on mechanical properties. Titanium matrix composites and titanium aluminides have also been extensively studied for future application in high-pressure compressors. In addition, in this study, melting technology of titanium alloys has been introduced.

    9. Scanning transmission electron microscopy measurement of bismuth segregation in thin Ga(As,Bi) layers grown by molecular beam epitaxy

      Thomas Walther, Robert D. Richards and Faebian Bastiman

      Article first published online: 3 JUL 2014 | DOI: 10.1002/crat.201400157

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      Annular dark-field imaging in a scanning transmission electron microscope has been used to measure concentration profiles across thin Ga(As,Bi) layers, from which the segregation lengths for bismuth surface segregation have been calculated. Performing this for layers grown at two different temperatures, the activation energies for bismuth surface segregation have been determined for both interfaces. The upper (GaAs-on-GaAsBi) interface is wider but exhibits slightly higher activation energy for surface segregation.

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