bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the fermi level, fermi distribution and activity coefficient for p‐SiC(Al)
Authors: Lilov S. K. 
Published: January 2007

AbstractA calculation was made of the Fermi level value and Fermi distribution at different temperatures, concentrations of impurities and degrees of compensation in acceptive silicon carbide, doped by aluminium. The dependence of the activity coefficient of aluminium in the silicon carbide on the concentration and the temperature was established.
The pAl0.7Ga0.3As‐pGaAs‐nGaAs concentrator cell with electrolytical contacts
Authors: Prutskij T. A. , Purón E. , Rodríguez J. A. , Romero R. , DeRoux S. 
Published: January 2007

AbstractThe technological procedure involved in making p‐Al0.7Ga0.3As‐p‐GaAs‐n‐GaAs concentrator solar cells by forced cooling LPE is discussed. Electrical contacts were electrochemically deposited from acid baths of Au and Ni, followed by annealing. 1.4 A/cm2 short current densities and 1 V open circuit voltages were measured under 7 W/cm2 incident radiation.
The incorporation of oxygen impurities in semiconductor silicon in chemical vapour deposition
Authors: Bartsch K. , Wolf E. 
Published: January 2007

AbstractThe incorporation of oxygen traces in chemical vapour deposited semiconductor silicon has been calculated for the temperature range of 1200–1500 K in dependence on the excess of hydrogen in the reaction gas. The results obtained correspond to the experimental data. With increasing temperatures of deposition and increasing excess of hydrogen the incorporation of oxygen decreases at a constant concentration of oxygen in the initial state.
DKDP Crystals for Electrooptic Devices
Authors: Ittu Zugrav M. , Dumitrica A. , Dumitras A. , Comaniciu N. 
Published: January 2007

AbstractThe deuterated homologue of potassium dihydrogen phosphate crystals (DKDP) was grown by a modified transport method. Experimental results concerning electrooptic characteristics of these single crystals used in construction of a Q‐switch and a four‐crystals modulator are presented. An infrared extension of KURTZ‐ROBINSON model electrooptic effect is also given.
Chemical Etching of Calcite Cleavages by Diluted Solutions
Authors: Mehta B.J. 
Published: January 2007

AbstractVery low concentration of mineral acids and monocarboxylic acid (less then 0.001%) produces triangular etch pits on calcite cleavages at dislocations intersecting the surface. The orienation of triangular etch pits is opposite with respect to percussion mark on calcite cleavages. This may be due to opposite process of percussion and reaction at very low concentrations. When percentage of water is slightly decreased in both above acids, rhombic etch pits were formed. The non‐coincidence of depth points and geometerical centres of rhombic etch pits are explained. The similarity of shape cycle will not hold at higher concentrations.
Investigation of the Microstructure of Crystals Surfaces by the Method of Self‐decoration during Ion Bombardment
Authors: Marinov M. , Stoyanchev R. 
Published: January 2007

AbstractA method is developed for self‐decoration with ion bombardment by which the surface structure of crystal samples is investigated. The existing surface structure of the objects, as well as the additionally developed structure after prolonged ion bombardment are visualized by this method. When using scanning electron microscopy the method allows multiple investigation of the sample or of one and the same parts of it respectively.The mechanism of the method is revealed by the results obtained in the performed experiments. It is proved that the crystal surface and its decoration depend on the peculiarities of the crystal structure and on the conditions of bombardment. By varying the conditions of ion bombardment the sensitivity of the method is considerably changed.
Single Crystal Growth and Pyroelectric, Dielectric, Piezoelectric, Elastic, and Thermoelastic Properties of Orthorhombic Li2SiO3, Li2GeO3, and Na2GeO3
Authors: Haussühl S. , Liebertz J. , Stähr S. 
Published: January 2007

AbstractSingle crystals of optical quality of isotypic Li2SiO3, Li2GeO3, and Na2GeO3, space group Ccm21, with diameters of ca 16 mm and lengths of ca 20 mm (Li2SiO3) and ca 60 mm (Li2GeO3 and Na2GeO3) have been grown from the melt using the Czochralski technique. On Li2SiO3, Li2GeO3, and Na2GeO3 pyroelectric coefficients and complete dielectric, piezoelectric, elastic, and thermoelastic tensor properties have been determined; the latter from the temperature dependence of resonance frequencies. All crystals investigated exhibited only a small amount of 180° twins. They all possess large pyroelectric coefficients about‐five times that of tourmaline. The longitudinal piezoelectric constant d333 is about five times larger than d111 of alpha quartz. Qualitative measurements on Na2SiO3 revealed similar values of pyroelectric and piezoelectric effects. The technical application of these crystals encounters some difficulties: Li2SiO3 is excellently cleavable parallel (010). This face contains the polar direction [001]. Na2GeO3 suffers from chemical decomposition in humid atmosphere and is well cleavable too. Both happens to a much less extent in Li2GeO3. Na2SiO3 proved to be hardly suitable for any application of its polar properties due to its bad chemical stability against humid air and its excellent cleavage.
Applicability of the Method of VAN DER PAUW to Samples with Two‐dimensional Defects
Authors: Albers C. , Gertig H. , Reuter M. 
Published: January 2007

AbstractThe influence of cleavage steps and low angle boundaries on the results of conductivity and Hall measurements by Van der Pauw's method are investigated and some criterions for evidence of sample inhomogeneities by the assumption of symmetrical sample shape and contact arrangement formulated. Hall voltage is less influenced by cleavage steps, so that the determination of carrier concentration is nearly correct also in strongly disturbed samples. Conductivity and carrier mobility measurements in the usus usual calculation procedure will lead to considerable errors. By one pair of contacts only for conductivity as well as for Hall measurements, the influences of inhomogeneities cannot be distinguished from volume effects of the sample.
Rotational Striations and Diffusion in Barium Sodium Niobate Crystals
Authors: Aleksandrovskii A.L. , Naumova I.I. , Posmykiewicz P. 
Published: January 2007

AbstractThe possibility of inducing rotational growth striae with a small period in barium sodium niobate crystals (BSN) is examined. Crystals grown had a period stability up to 1 percent and were suitable material for anisotropic light diffraction by ferroelectric domains. However intense striae were produced only for periods λ > 5 m̈m. With the help of Bragg optical diffraction by growth striae the diffusion coefficient D in solid phase responsible for striae smoothing during annealing was measured. The magnitude D ≈ 10‐11 cm2 s‐1 at the melting point was obtained. Such D value leads to the vanishing of striae with λ < 5 m̈m in BSN crystals during growth.
A New Method for Powder Diffraction Phase Analysis
Authors: Fiala J. 
Published: January 2007

AbstractA new method for quantitative X‐ray phase analysis is described. This universal procedure allows to analyse mixtures of components some of which are not known or partly known substances.Es wird ein neues Verfahren der quantitativen rötgenographischen Phasenanalyse beschrieben. Dieses universelle Verfahren ermöglicht, Gemische von Komponenten, die unbekannt oder teilweise unbekannt sind, zu analysieren.
Influence of Additives and Surface Topography on the Alignment of Nematic Liquid Crystals
Authors: Hauck G. , Komitov L. , Derzhanski A. , Koswig H. D. 
Published: January 2007

AbstractObservations of the influence of a simultaneous action of different surface topographies and polar or nonpolar additives in small concentration on the alignment properties of liquid crystal molecules are reported. The additive dependence of the threshold behaviour of planar aligned liquid crystal cells is also studied.
On the Influence of the Distortion Distribution on the Determination of Roentgenographic Particle Sizes and Distortions (II) Distortion Distributions and Evaluation Procedure
Authors: Röll H. , Schulz H. 
Published: January 2007

AbstractIt is shown that a Gaussian distribution of the distortion not enables in each case an exact evaluation of experimentally measured Debye‐Scherrer lines. – After a discussion of simple possibilities for set up of simple and more common distortion distributions with more than one free parameter is given a procedure independent on the distortion distributions for the determination of roentgenographic particle sizes and distortions.
Hydrothermal Synthesis and Characterization of VSZ‐3 Zeolite Crystals
Authors: Joshi M. S. , Mohan Rao P. , Choudhari A. L. , Kanitar Ravindra 
Published: January 2007

AbstractZeolite crystals (named here VSZ‐3) synthesized at 350°C by hydrothermal method are illustrated and described. These crystals are shown to be analcime type zeolites. It is established that their size is the largest among the zeolite crystals ever reported, and are stable upto 1000°C. The VSZ‐3 crystals are prismatic pyramidal and needle‐like. They are characterized by X‐rays, SEM, TGA, DTA and IR. Their chemical composition is shown to be 5.95 SiO2 ṁ Al2O3 ṁ 0.91 Na2O ṁ 0.17 H2O. Mechanism of growth of these crystals is explained.
Etch Pit Morphology on Calcite Cleavages by Glacial Acetic Acid
Authors: Mehta B. J. 
Published: January 2007

AbstractEtch pit morphology has been studied on calcite cleavages by different concentration of glacial acetic acid. Lateral reaction rates are very less at high concentration as well as low concentration of glacial acetic Acid. Etch pit morphology changes due to formation of finite or infinite lateral reaction rates at some particular concentration called transition concentration. The underlying chemical equations are given for different etch pit morphology.
Ihnomogeneous Distribution of Doping Elements in Polycrystalline GaP
Authors: Moravec F. , Štrajblová J. 
Published: January 2007

AbstractThe distribution of Te and Zn in polycrystalline GaP ingots grown by SSD method was studied by means of the contact resistance measurements between a tungsten carbide probe and a lapped sample surface. The differencies in carrier concentrations measured in differently oriented GaP :Te crystal grains were found as high as one order of magnitude. In GaP: Zn crystals the constant Zn concentration throughout the sample was observed.
The Extrapolation Method in the Electron Probe Microanalysis
Authors: Christ B. , Oelgart G. 
Published: January 2007

AbstractFrom the energy dependance of the k‐ratio measured for the SbLα and BiLα‐lines in the alloy system Bi1–xSbx the k‐ratio at the critical energy Ec is determined by extrapolation. The stopping power correction is discussed for the system investigated here on the basis of the known composition of the specimens. The mean ionization potentials J for Sb and Bi are estimated from the experiments.
Revelation of microtwinning in hydrothermally grown synthetic quartz by growth structures
Authors: Kotru P. N. , Raina K. K. 
Published: January 2007

AbstractGrowth structuress on prism surfaces of synthetic quartz grown by hydrothermal crystallization technique, indicative of microtwinning in them are described, illustrated and discussed. The microtwins are revealed by the misorientation of the growth structures, and it is observed that microtwinning is manifested in different forms. Twinned domains appear in the form of strictly oriented, square striated (stepped) structures with inclined surfaces, seemingly overlapping square striated structures, square and irregular regions demarcated by black line‐like boundaries, patch‐like structures enveloping irregularily bound domains, tongue‐like terraces bordered by irregular line of discontinuity of varying height and the regions with both differently shaped as differently oriented growth structures. From the orientations of the square shaped growth structures, it is shown that crystals consist of domains which are in twin relationship to the main crystal. Twins by rotation around an axis perpendicular to (10ī0) with rotation angles of 60°, 90°, and 180° have been observed. Critical examination of some twin boundaries delineated by black line‐like matter, with the application of multiple beam interferometry and FECO reveal that the black boundary is a ridge (line‐elevation). The line elevation along such a twin boundary is explained to be as a result of preferential adsorption of impurity atoms along the trace of the boundary. It is further observed that discontinuity in crystalline structure along the twin boundary leads to growth forms with distorted morphology thus establishing strong dependence of growth forms on the underlying crystalline structure. Causes for generation of the microtwins (twinning on a microscale) in synthetic quartz are discussed.
The effect of divalent impurity state on the microhardness of NaCl crystals
Authors: Andreev G. A. , Klimov V. A. 
Published: January 2007

AbstractThe microhardness and bulk density variations with annealing temperature have been measured in NaCl crystals doped with Ca2+, Cd2+, Ni2+, and Pb2+. Both characteristics are not affected by coherent metastable precipitation while incoherent precipitation produces either hardening or softening depending on the impurity phase type (stable or metastable). The results support the suggestion that aggregates and coherent precipitates are cut through by dislocations whereas incoherent precipitates are by‐passed via the Orowan looping mechanism.
Dehydration of Selenite Cleavage Faces
Authors: Mehta B. J. 
Published: January 2007

AbstractInitial dehydration of selenite cleavage surfaces start at temperature 86 °C. The dislocations are revealed by distilled water. Dislocations are mobile at dehydration temperature. Impurity centres may act as obstacles for dislocation movement. Dehydration figures are in probability formed at impurity centres.
Mikrohärteuntersuchungen an Einkristallen der Verbindungen Tl3BX4, (B = V, Nb, Ta; X=S, Se)
Authors: Wacker K. , Buck P. 
Published: January 2007

AbstractVickers microhardness measurements were performed on single crystals of compounds Tl3BX4 (B = V, Nb, Ta; X = S, Se). The anisotropy of the hardness on the (111)‐plane was beyond the standard deviation. Besides the load‐dependent Vickers hardness HV, the corrected, load‐independent hardness HVc was determined. Tl3VS4 showed the highest value of hardness (HV = 66 kp/mm2 at 15 p load), the othe compounds differ only slightly in hardness.
A Model Study of the Growth of Crystals Consisting of a Small Number of Metal Atoms by the Hückel Molecular Orbital Method (II) Addition of One Atom to (N + 1)‐atomic Clusters
Authors: Delineshev S. P. , Bliznakov G. M. 
Published: January 2007

AbstractThe regularities of the formation of (N + 2)‐atomic clusters obtained by the growth of (N + 1)‐atomic clusters and the distribution of the (N + 2)‐atomic clusters according to their stability are studied. The most stable (N + 2)‐atomic cluster is not always obtained from the most stable (N + 1)‐atomic cluster. Sometimes it is formed by the least stable (N + 1)‐atomic cluster.A necessary condition for the appearance of the most stable (N + 2)‐atomic cluster is the formation of a bond between the N + 2nd and the N + 1st atoms. This means that the most stable (N + 2)‐atomic cluster may be considered as obtained directly from the N‐atomic crystal by jumping over the stage of the (N + 1)‐atomic cluster and adding a dimer suitably oriented with respect to the N‐atomic crystal.The least stable (N + 2)‐atomic cluster is always obtained from the least stable (N + 1)‐atomic cluster.
Structure Changes in an Al‐4.5 at.% Zn‐2.0 at.% Mg Alloy during Continuous Heating in Dependence on the Starting Conditions
Authors: Oettel‐Gueffroy B. , Löffler H. 
Published: January 2007

AbstractThe structure changes proceeding during continuous heating of an Al–Zn(4.5 at.%)–Mg(2.0 at.%) alloy were investigated by DSC and SAXS in dependence of the start radius, rS, of the metastable phases (G.P. zones and/or η'‐phase) ranging from rS = 0.7 nm to 2.7 nm grown at Tpre = R.T. or 100°C. The stability of the metastable phases grown at Tpre is increasing with the ris e of rS, whilst the Tpre applied does not remarkably affect their stability. Starting with rS > 1.6 nm the minima in the DSC‐curve caused by the formation of η'‐phase on the expense of the dissolved part of the zones (1. minimum) or from overcritical G.P. zones (2. minimum) become more and more undistinct with the rise of rS.
The MORIN Transition – a Sensitive Criterion for Testing the Quality of α‐Fe2O3
Authors: Fritzsch E. , Pietzsch C. , Heegn H. , Huhn H.‐J. 
Published: January 2007

AbstractThe MORIN transition of α‐Fe2O3 is quite sensitive to impurities, lattice imperfections and particle size and, therefore, can be used to test the quality of α‐Fe2O3. If in the material under consideration the MORIN transition has completely taken place at 250 K, the material is pure, undistorted bulk α‐Fe2O3. For testing this only one Mössbauer spectrum has to be taken at 250 K.
Growth of Heterostructures Based on InAs–AlxGa1–xSb
Authors: Pramatarova L. D. , Tret'Yakov D. N. 
Published: January 2007

AbstractIt is reported on the liquid phase epitaxial (LPE) growth of heterostructures on the base of InAs–AlxGa1–xSb. The paper includes the investigation of epitaxial layers of AlxGa1–xSb alloys on InAs substrates and results of experiments for the determination of optimum growth regimes.
Laser Annealing of Chemical Bath Deposited CdS Films
Authors: Martinez G. , Martínez J. L. , Zehe A. 
Published: January 2007

AbstractChemical Bath Deposited (CBD) CdS films have been exposed to a cw Ar+ laser annealing. Measurementes on the dark electrical resistivity have shown a two decade decrement in the resistivity. A trend of improving this resistivity is shown upon atmospheric pressure increase. The annealing mechanisms of the samples show a threshold laser power density of 50 W/cm2. This power threshold accounts for some heating mechanisms and Cd ion evaporation from the samples; thus a gaseous Cd atmosphere annealing process is suggested. This laser annealing mechanism parallels thermal annealing of polycrystalline CdS films. Assessment of this mechanisms is supported by the fact that the mobility ratio, b = μn/μp, (greatly influenced by crystallite size and intergranular potential barrier in thin film semiconductors) does not show major changes to account for a two decade decrement of CBD laser annealed samples.
Zinc Oxide with High Luminescence in the Ultraviolet Region
Authors: Klikorka J. , Lošťák P. , Horák J. , Fojtík L. 
Published: January 2007

AbstractIn the present work a preparation of ZnO showing high luminescence in the region of the interband transitions at about 385 nm is described, while luminescence in the green region is practically suppressed. The preparation consists of increasing the free carrier concentration by incorporation of Ga3+ ions into the ZnO lattice and decreasing further the concentration of oxygen atoms by annealing in a reducing in a reducing atmosphere. It has been shown experimentally that by using lead‐doped ZnO, the ration of band intensities in the UV and green regions is substantially higher than when ‘pure’ ZnO is used. We present finally a possible explanation of the role of Pb atoms bringing about this phenomenon.
Orientation relationships of aluminium nitride on sapphire
Authors: Sokolov E. B. , Malyukov B. A. , Kudakov U. D. , Naida G. A. 
Published: January 2007

AbstractOrientation relationships of aluminium nitride on sapphire (1126) AlN/(0112) Al2O3 have been defined more exactly by X‐ray diffractometry techniques. It has been found that, depending on the substrate misorientation from the surface plane (0112), there can exist two kinds of azimuthal orientation of the epitaxial layer of AlN, namely, the projection of [0001] AlN on plane (0112) Al2O3 can coincide either with [2110] Al2O3 or with [2110] Al2O3 direction.The vector field of the epitaxial layer inclination relative to the substrate misorientation has been drawn. The symmetry of this field obeys Neumann's rule. The epitaxial layer orientation has been found to depend on the sapphire substrate misorientation in direction [2110].
Investigations of flash evaporated cubIIIC2VI semiconductor thin films by Rutherford backscattering spectroscopy
Authors: Höbler H.‐J. , Flagmeyer R. , Schumann B. 
Published: January 2007

AbstractThe chemical composition of CuBIIIC2VI thin films grown by flash evaporation technique was analysed using Rutherford backscattering spectroscopy. The composition of the samples changes with variation of the substrate temperature. In certain temperature ranges nearly stoichiometric layers were obtained.
The influence of the lattice misfit on the growth of CuGaSe2 Epitaxial Films on {100}‐oriented GaAs and GaP Substrates
Authors: Schumann B. , Tempel A. , Kühn G. 
Published: January 2007

AbstractCuGaSe2 epitaxial layers were prepared on GaAs and GaP {100}‐oriented substrates by flash evaporation technique and characterized by RHEED. Different epitaxial relationships have been found for growth on the different types of substrate material. The orientation is determined by the minimum misfit.
A New polytype notation for CdI2 type structures. The thr symbols
Authors: Fichtner K. 
Published: January 2007

AbstractThe thr notation is introduced to describe any stacking variant as a mixture of fractions of the three simplest or regular polytypes: 2H (trigonal), 4H (hexagonal), and 6R (rhombohedral). The new notation is compared with existing ones and applied to pairs of homometric structures and to the characterization of stacking faults.
Peculiarities of reoriented bands formation in crystals
Authors: Berezhkova G. V. , Perstnev P. P. , Romanov A. E. , Vladimirov V. I. 
Published: January 2007

AbstractThe peculiarities of the formation and the development of reorientated bands in crystals are considered. Reorientated bands are investigated experimentally in MgO single crystals under the compression testing. It is shown that the misorientation between the material in the band interior and the surrounding volume can reach some degrees. The data of electron microscopy investigations of dislocation structure of such bands are performed. The disclination model is proposed for the propogation of the reorientated bands. This model permits to explain the laws of the band development, for example, the formation of discrete areas with reoriented crystal lattice ahead the terminated band.
Elastic debye temperature of compounds with sphalerite structure
Authors: Deus P. , Schneider H. A. 
Published: January 2007

AbstractElastic Debye temperatures θEL of the semiconducting compounds AIIIBV, AIIBVI and CuCl are evaluated from second order elastic constants Cik available from the literature. The dependence of θEL on temperature is given. The results at 0 K are compared with those calculated from low temperature measurements of specific heat. Generally, the agreement between these values is better than found in the literature up to now.