bluuebunny/crossref_metadata_2025_split huggingface dataset:
A combination of oscillating slit and oscillating film techniques for the investigation of lattice defects
Authors: Auleytner J. , Furmanik Z. 
Published: January 2007

AbstractA combination of oscillating slit and oscillating film techniques is described. This X‐ray topographical method allows reflections due to the same places on the crystal surface to be recorded first in form of a topogramme registrated on the oscillating film set in the parallel position to the crystal surface. Second on the stationary film set parallel to the crystal surface in the form of an interference line Kα1 or Kß outgoing from the investigated area and registrated on the first topogramme at the fixed angular position of the crystal and slit and next, recorded separate on the oscillating film and on the stationary film set in the distance of 50 mm from the crystal (oscillation axis). As an example a serie of photographs corresponding to four types of pattern obtained in the case of a PbSnTe crystal with small angle boundaries are presented.
On iodine behaviour in bulk crystals of PbTe and SnTe synthesized by the iodide method
Authors: Trifonova E. P. , Karagiozov L. 
Published: January 2007

AbstractIn order to explain the peculiar characteristics of iodidely synthesized PbTe and SnTe crystals a model for their interaction with iodine is suggested. It is based on the assumption that PbI and I, respectively SnI and I, resulting from the PbI2 (SnI2) dissociations, are incorporated independently and specifically in the crystals: in PbTe prevails the PbI‐incorporation; in SnTe — the incorporation of I + VSn. This difference is connected with the thermodynamic stability of the PbTe and SnTe crystal lattices.
Anisotropy of temperature factors and interatomic forces in II‐IV‐V2 semiconductors
Authors: Vaipolin A. A. 
Published: January 2007

AbstractAn imcomplete set of X‐ray reflections with high indices („back”︁ reflections by MoK‐radiation) was measured for six II‐IV‐V2 semiconducting compounds of the chalcopyrite structure. The site parameter of the V‐atom and the temperature parameters proportional to the components of mean square displacements of atoms () were determined. General peculiarities of the relation of temperature factor constants and its variation within this family of compounds are reported. A qualitative crystallochemical interpretation of this relation is proposed on the basis of the atomic interaction scheme taking into account the principal and auxiliary bonds in the first and the second coordination sphere, respectively.
The melt growth of semicircular crystals of the pure Pb and its dilute alloys
Authors: Hayashi S. , Fukui M. , Komatsu H. 
Published: January 2007

AbstractSemicircular crystals of Pb were grown from the melt by a rotational operation so as to change the orientation of the solid‐liquid interface during crystallization. In pure Pb, specimens grew as polycrystals with grain boundaries developed transversely to the growth direction. According to the decrease in purity, the grown crystals consisted of several long grains along the circular arc. A competitive growth between grains was inhibited by a small amount of impurity and then the mode of growth approached to the complete adhesive one.
On the structure of α′m‐precipitates in Al‐Zn alloys
Authors: Werner M. , Löffler H. 
Published: January 2007

AbstractThe lattice parameter of the f.c.c. α′‐phase in an Al‐12at.% Zn alloy decomposed at ageing temperatures ranging between 170 °C and 210 °C was investigated by an analysis of Moiré fringe contrasts which appear inside the precipitates in the TEM‐micrographs. Additionally information was gained concerning the relationship between the corresponding lattice of the α′m‐precipitates and the matrix. The analysis proved that the misfit between the lattice of the α′m‐precipitates and the adjoining matrix is fairly small, namely less than 1.5% in lattice spacing and less than 1° in the angular rotation. From these results it was concluded that the major part of the matrix planes passes the precipitates without interruption.
SIMS‐AES investigations on water vapour adsorption on nickel (100) at room temperature
Authors: Uhlmann K. , Storbeck F. , Griessbach R. 
Published: January 2007

AbstractBy means of the methods SIMS and AES the adsorption of water vapour on the (100) surface of nickel was studied. We conclude from the results obtained that the adsorption has three stages: chemisorption of OH groups, formation of a surface hydroxide and finally, formation of an oxide layer containing O and OH. The quantity of oxygen detected corresponded maximally to about a monolayer coverage.
Influence of intrinsic defects on the electrical properties of AIBIIIC compounds
Authors: Neumann H. 
Published: January 2007

AbstractThe electrical parameters of undoped melt grown AIBIIICVI2 crystals are compared with predictions which can made considering the deviations from stoichiometry due to the incongruent evaporation of these compounds. It is shown that the electrical properties of all AIBIIIC compounds can be interpreted in a consistent manner if the electrical activity (donor or acceptor) of the intrinsic defects is considered in the covalent bonding model.
Defect levels in the energy gap of the PbI2 crystal evidenced by optical methods
Authors: Constantinescu M. , Ghit˘ L. , Baltog I. , Ghit˘ C. 
Published: January 2007

AbstractA scheme of the localized levels in the energy gap of PbI2 single crystal is deduced on the base of our experimental studies of luminescence, photoconduction and thermo‐stimulated currents on crystals as grown or submitted to a specific thermal treatment and optical irradiation.
Textural properties of AISb films
Authors: Patel S. M. , Biradar A. M. 
Published: January 2007

AbstractTextural studies have been carried out in AlSb films deposited by coevaporation method under high vacuum at different substrate temperatures between 450° to 625 °C. The films have been examined by X‐ray and electron diffraction techniques. It was observed that the films deposited around 550 °C were found to exhibit [110] and [111] textures and the films deposited at higher substrate temperatures (above 600 °C) were found to exhibit only [111] textures.
Mode of solidification and strength properties for lead‐tin binary system
Authors: Bassi P. S. , Sharma N. K. , Chawla J. S. , Sharma M. K. 
Published: January 2007

AbstractTensile strength and ductility of unidirectionally and randomly solidified Sn, Pb and Sn–Pb eutectic alloy are determined. Appreciable increase in the ductility from random to directional growth has been observed in case of Sn, Pb and Pb–Sn eutectic. Improvement in tensile strengths of pure metals and their eutectic composite by 15–20% and 15%, respectively, was evident in case of directionally solidified to randomly grown samples. The increase in tensile strength of the eutectic was 2–2.5 times to the strength of the pure metals. Tensile strength of directionally solidified Pb–Sn eutectic studied at different rates of solidification for constant temperature gradient was lower at higher and at lower rates of solidification than the value at medium rates of solidification.
Temperature distribution in growing semi‐transparent crystals (III). Conical liquid/solid interface
Authors: Kvapil Jiří , Kubelka J. , Kvapil Josef , Perner B. 
Published: January 2007

AbstractTemperature distribution in Al2O3 and YAG crystals grown by Czochralski method and in the melt layer adjacent to the liquid/solid interface of the conical shape was computed. The results were compared with the quality of the crystals. Using a highly absorbing material, temperature difference near the deeply submerged sharp interface decreases from the edge to the centre of a crystal and it is relatively great and unalterable in the case of a shallowly submerged blunt interface. Sharp interface show the crystals grown from the melt of the same composition (Al2O3 or accurately “stoichiometric” YAG), whereas the blunt one is typical of YAG grown from the melt of the “non‐stoichiometric” composition, because its solidifying point is below the melting point of YAG phase.
Influence of the flow velocity, supersaturation and temperature on the crystal growth from solutions
Authors: Kirkova E. , Nikolaeva R. 
Published: January 2007

AbstractThis paper is a review of our experimental research on the influence of the supersaturation, flow velocity and temperature on the linear crystallization rate of different faces of model crystal systems. The obtained experimental results are discussed in the light of the new theoretical treatments on crystal growth from low temperature solutions.
On the mechanism of chemical polishing of GaAs crystals
Authors: Zach D. , Löwe H. 
Published: January 2007

AbstractIn order to establish reproducible conditions for chemical lap polishing of GaAs with NaOCl solutions, containing also OH−‐ and CO ‐ions, the mechanism of dissolution was investigated using the rotating disk arrangement. In solutions with excess OCl− concentrations likewise diffusion and a reaction of the first order with respect to OH− and CO, complexing agents for Ga‐ions, control the dissolution rate, and the surfaces of the wafers are polished. OH− and CO32– concentrations in excess with respect to OCl− lead to rate determining OCl− diffusion and to irregularly polished or film covered surfaces. Diffusion constants for OH−, CO and OCl− are given.
Determination of the phase ranges during cooling and heating of Al‐40wt.%—(0—3) wt.% Mg alloys
Authors: Major B. , Ciach R. , Wendrock G. , Löffler H. 
Published: January 2007

AbstractThe various phases and the respective ranges of their existence were determined during continuous cooling from temperatures close below the solidus line to R.T. with a rate of 2 K min−1 as well as during the subsequent heating in few AlZn(40 wt.%)–Mg(X) alloys (X = 0; 0.5; 1.0; and 3.0 wt.%) by means of X‐ray phase‐analysis, small angle X‐ray scattering, differential thermo‐analysis, optical microscopy, and X‐ray micro‐analysis.The most striking features are that even addition of only 0.5 wt.% Mg cause the formation of precursors of the MgZn2 equilibrium phase few degrees below the solidus line.
Influence of the aggregation state of Sr2+ ions on glow curves behaviour of NaCl: Sr2+
Authors: Reddy K. Narasimha , Babu V. Hari 
Published: January 2007

AbstractGlow curves were recorded for NaCl:Sr2+ crystals subjected to annealing and quenching from elevated temperatures. These specimens were irradiated with X‐rays at room temperature by tungsten target. Samples exhibit certain glow peaks which are observed only in the first thermal cycle. A marked difference in the glow curves pattern for first and subsequent thermal cycles has been observed. It is suggested that these changes may be due to the change in configurational coordinate system of F‐centre due to impurity existing different states. This idea is supported by optical microscopy studies.
Results of crystal growth of bismuth‐antimony alloys (Bi100–xSbx) in a microgravity environment
Authors: Schneider G. , Herrmann R. , Krüger H. , Rudolph P. , Kuhl R. , Röstel R. 
Published: January 2007

AbstractResults of two experiments are presented for growth of crystals from (Bi100–xSbx) alloys in a microgravity environment. In the growth experiments different variants of the Bridgman technique were used.It was shown that in crystal growth from the melt in closed ampoules under microgravity conditions convection can be prevented completely. Therefore it is possible to grow crystals from melts of some components under diffusion controlled conditions of mass transfer.In microgravity a reduced interaction between the melt and the confining walls was observed even if they have large contact with each other. The investigation of surface morphology corroborated the importance of surface effects for crystal growth from the melt under microgravity conditions. Measurements of electronic properties of crystals grown in microgravity showed a good quality in comparison to earth grown crystals.Because under microgravity conditions in closed ampoules the diffusion controlled mass transfer can be realized and the interaction between the melt and confining wall is reduced, homogeneous crystals with high perfection can be grown melts of some components.
Influence of additives on periodic crystallisation in Gel(I). theory
Authors: Ambrose S. , Gnanam F. D. , Ramasamy P. 
Published: January 2007

AbstractA quantitative explanation is given for the influence of additives on periodic crystallisation in gel. The theory involves the diffusion of the outer, inner and the additive electrolytes. It is assumed that precipitation begins when the product of the concentrations of the reactants reaches a critical value. Expressions are found for the velocity constant and spacing coefficient incorporating the valency and concentration of the additive.
On the incorporation mechanism and distribution mode of impurities in potassium acid phthalate crystals grown from aqueous solutions
Authors: Gerasimov Y. M. , Distler G. I. , Kanevsky V. M. , Kortukova E. I. , Suvorova E. I. , Okhrimenko T. M. , Belikova G. S. 
Published: January 2007

AbstractMechanism of impurity structure formation in crystals grown from aqueous solutions has been studied on the example of potassium acid phtalate (abbreviated hereafter as KAP) single crystals. Gold decoration technique at an electronmicroscopic scale has been applied to the study of the distribution of uncontrolled impurities on KAP cleavage face (010) after 10, 20 and 30 days of growth, taking into consideration different growth rates in 〈001〉 and 〈001〈 directions. A technique for visualization of impurities in water, based on the adsorption of these impurities by the surface of amorphous film of nitrocellulose (parlodion) and the vacuum decoration with gold of these impurities, has been developed.Differences in the impurity structure of KAP regions located in 〈001〉 and 〈001〉 directions from the seed have been established. In 〈001〉 direction after 20 days of growth impurity assemblies 0.1—0.4 μm in size are revealed, and in 〈001〉 direction heterogeneous impurity structure is revealed only after 30 days of growth. The real (impurity) structure of KAP outside impurity assemblies is quite homogeneous and is the same throughout the whole crystal volume, the impurities incorporating mainly into complex active centres. From comparison of the changes in time of the impurity structure of water used for crystallization solutions and the impurity structure of KAP crystals a conclusion is made that the impurity structure of crystals is “programmed” in the impurity structure of crystallization solutions which regularly changes with time, i. e. impurities from different kinds of assemblies which are selectively adsorbed by the growing crystal faces. The role of the adjacent to the growing face interfacial layers which control the growth rate and have a complex impurity structure is stressed.
State of dispersion of impurity on formation of Z1‐centres in NaCl:Sr2+ crystals
Authors: Reddy K. Narasimha , Rao U. V. Subba , Babu V. Hari 
Published: January 2007

AbstractThermoluminescence (TL) and Optical absorption studies are carried out to study the bleaching kinetics of F‐centre and formation of Z1‐centres in X‐irradiated strontium doped NaCl crystals, both in as‐grown state and in quenched state. An additional TL peak is observed in this crystal system after F‐bleaching of irradiated samples which is attributed to thermal annealing of Z1‐centres. Various models proposed for Z1‐centres are reviewed in the light of these results and it is concluded that Z1‐centres are associated with impurity‐vacancy dipoles.
On the adsorption‐ and equilibrium‐referred interpretation of the doping element incorporation during the growth of CVD epitaxial silicon
Authors: Kühne H. 
Published: January 2007

AbstractFür die Betrachtung der Teilschritte des Dotandeneinbaus: Gastransport, Adsorption‐Desorption, Einbau, erhält man nur dann eine den kinetischen Einfluß des Schichtwachstums befriedigend wiedergebende Lösung, wenn man für den Einbauschritt spezielle Hinund Rückreaktionsmechanismen in Ansatz bringt. Trotz der Annahme eines thermodynamischen Zerfallgleichgewichts für die Dotandenquellsubstanz und von Einbaugleichgewichten für die einzelnen Komponenten des Zerfallsgleichgewichts sind die Komponenten des Zerfallgleichgewichts als Quelle für die Bildung des Dotandeneinbaustroms nicht gleichberechtigt. Im Einbaugeschehen dominiert diejenige Komponente mit dem größten relativen Gleichgewichtspartialdruck.
On the scandium distribution in indium arsenide crystals grown by the Czochralski method
Authors: Lilov S. K. , Yakimova R. T. 
Published: January 2007

AbstractIn this paper the behaviour of scandium in n‐type monocrystalline indium arsenide grown by Czochralski method in sealed ampoule is studied. The crystals have been grown in [111] direction under different conditions: crystallization rate, As‐partial pressure and scandium initial concentration in the melt. The effect of the above factors on the scandium distribution along the crystals have been investigated. Using these results and by means of the equation of normal freezing the effective Sc distribution coefficient (k) in InAs under different technological conditions has been determined. It has been found that k < 1 in all experiments. In order to find the equilibrium coefficient (k0) at fixed growth conditions the Burton‐Prim‐Slichter model has been used. On the basis of Hall measurements and atomic absorption analysis of Sc‐doped InAs it is concluded that connected with Sc electrically active centers behave as shallow donors, most probably monovalent ones.
Increase of sensibility of X‐ray diffraction technique for investigation of quartz monocrystal perfection
Authors: Zargaryan Y. G. , Bezirganyan P. H. , Adamyan S. A. 
Published: January 2007

AbstractIt is shown that for the increase of sensibility of X‐ray topogram methods to investigate the slantwise cut quartz monocrystal, the external electrostatic field of a certain magnitude should be applied on the sample.
Calculation of the cyclic hardening curves of fatigued FCC monocrystals using a two‐phase model
Authors: Blochwitz C. 
Published: January 2007

AbstractThe cyclic hardening curve of fatigued fcc monocrystals shows a maximum of the stress amplitude if the plastic resolved shear strain amplitude γap exceeds the threshold value γM for the formation of persistent slip bands (PSBs). Using a simple two‐phase model the typical shape of the cyclic hardening curve will be calculated for lower γap values. The calculation takes into account the fact that the PSB formation starts already at a „nucleation stress”︁ amplitude τn below the maximum stress amplitude τam. Qualitatively the maximum of the cyclic hardening curve follows from the superposition of cyclic hardening of the matrix volume and of volume growth of the „soft”︁ PSB phase between the nucleation cycle number Nn and the saturation cycle number Ns.
Glow curves of flux‐grown NaMgF3 crystals
Authors: Reddy B. Kantha , Somaiah K. , Babu V. Hari 
Published: January 2007

AbstractGlow curves and optical absorption spectra of X‐irradiated flux grown crystals are studied. Two glow peaks at 370, 585 K and three shoulders at 420, 540 and 610 K are obtained. Optical absorption studies reveal two absorption bands at 405 and 475 nm and a well defined peak at 295 nm. Room temperature annealing and bleaching studies have suggested that the glow peaks at 370 and 585 K may correspond to impurities and F‐centers of 295 nm band respectively. The other shoulders at 420, 540 and 610 K are attributed to other F‐aggregate centers. The glow peaks are analysed using first order kinetics.
Crystallization of a germanium melt in an external electric field
Authors: Kanter Yu. O. 
Published: January 2007

AbstractData are presented on experimental studies of the influence of an external electric field on crystallization of a germanium melt under the layer of a B2O3 flux. It has been found out that with the field supercoolings of the melt sharply change. This effect is due to the change of the number of active nucleation centres at the germanium – B2O3 flux interface. The maximum supercoolings of the germanium melt ΔT− = 190 K were obtained when a negative potential was connected to germanium. The dependences of supercooling on preliminary melt overheating were measured.
The texture of GaSb ingots grown by the bridgman method
Authors: Koltai F. , Hársy M. , Lendvay E. 
Published: January 2007

AbstractCrystallographic features of GaSb grown by the Bridgman procedure were investigated by scanning electron microscopy. Chemical etching and the electron channelling method were used to determine the position and crystallographic orientation of crystallites. A pronounced 〈110〉 texture was detected which was misaligned by 5÷28° with respect to the main axes of the ingots. Boundaries were categorized according to the orientation change accross them. Results were compared. The majority of small angle boundaries are probably caused by thermal stresses induced dislocation migration.
The influence of gas‐phase etch removal, deposition temperature and substrate properties on the crystallographic perfection of silicon epitaxial layers
Authors: Richter F. , Weidner G. , Borchardt A. , Bugiel E. , Kittler M. , Schmalz K. , Weidner M. , Rausch H. 
Published: January 2007

AbstractAn investigation of the defect structure of silicon homoepitaxial layers, as influenced by gas phase etching, deposition temperature, and substrate properties, is presented. The minimum values of etch removal and deposition temperature necessary for sufficient layer perfection have been determined. The defect and impurity distribution in the substrate, as formed during a preceeding arsenic buried layer processing, have been evaluated and are discussed here with regard to their influence on the epitaxial layer perfection.
Growth of calcium phosphate crystals in Silica gel
Authors: Kibalczyc W. , Sokołowski T. , Wiktorowska B. 
Published: January 2007

AbstractThe results of a study of the crystal growth of calcium phosphates in silica gel employing double diffusion system with CaCl2 and KH2PO4 aqueous solutions are reported. Liesegang rings, spherical crystalline agglomerates and brushite dendrites are formed near the CaCl2 solution. It was found that the agglomerates consist of octacalcium phosphate and hydroxyapatite crystals with the predominance the former.
On some experiences with the thr notation for CdI2 polytypes
Authors: Fichtner K. 
Published: January 2007

AbstractThe advantages of the thr notation are discussed using 12 recently reported polytypes as examples. It is shown that the thr notation combines the advantages of the Zhdanov notation with those of the t‐o‐f notation. An almost trivial conversion of Zhdanov sequences into thr sequences and vice versa is given. The restrictions in the stacking of CdI2 polytypes and the relations between homometric structures can be described in the most simple way using the thr notation.
Study of electrical properties in mixed oxide sandwich structures
Authors: Siva Kumar J. , Narayana G. , Chandra Shekar M. , Subba Rao U. V. , Hari Babu V. 
Published: January 2007

AbstractI—V characteristics of sandwiched Al—(SnO2 + Sb2O3)—Al mixed films have been studied for different thicknesses. The current‐voltage curves in general exhibit three regions, ohmie, non‐ohmic and breakdown regions. The breakdown voltage increases and the dielectric strength decreases with increase of film thickness. The de breakdown studies have been done and optical photomicrographs of breakdown patterns during different stages of de voltage have been taken and the results are discussed.