bluuebunny/crossref_metadata_2025_split huggingface dataset:
In‐situ doping of and trench‐refill with LPCVD‐poly‐silicon (I). (PH3/SiH4) ratio as a process‐controlling parameter
Authors: Kühne H. , Harnisch H. , Flohr I. , Bertoldi W. 
Published: January 2007

AbstractThe ratio of phosphine‐ to silane concentration in the reaction gas mixture is a processcontrolling parameter in LPCVD‐polysilicon deposition not only with respect to doping level of the layer and layer growth rate on planar wafer surface, but also with respect to the degree of growth rate depression occurring by change‐over from wafer surface to sidewall area within trenches in the region of the upper rim of a trench. Trench refill behaviour deteriorates in consequence of growth rate depression within trench the more the higher the doping level of poly‐silicon will be chosen. Yet below a lower limit of doping poly‐silicon growth rate equals that of undoped poly‐silicon, and, as for trench‐refill, there is no difference in layer growth within trench and beyond.
Optical properties of flash‐evaporated CuInTe2 thin films
Authors: Hörig W. , Neumann H. , Savelev V. , Lagzdonis J. , Schumann B. , Kühn G. 
Published: January 2007

AbstractOptical absorption spectra of flash‐evaporated polycrystalline thin films of CuInTe2 are measured in the photon energy range from 0.5 to 3.0 eV. A gap energy in the range from 0.96 to 0.99 eV and a spin‐orbit splitting of the valence band of 0.61 ± 0.03 eV are derived from the spectra. It is found that the spectra are considerably influenced by grain boundary effects.
Solidification behaviour of BaB2O4 melts
Authors: Ovanesyan K. L. , Petrosyan A. G. , Shirinyan G. O. 
Published: January 2007

AbstractExperimental evidence has been obtained that both α‐ and β‐phase BaB2O4 material can be grown directly from pure melts. Growth of α‐phase material onto a platinum rod is initiated by α‐phase structural centers present in the melts which are stable at temperatures around or just above the melting point. Overheated melts in which solid nuclei are destroyed have modified freezing characteristics and form β‐phase material. β‐phase material can be produced onto a platinum rod at temperatures well above the reported phase transition temperature.
The coprecipitation of magnesium hydroxoaluminate hydrates from aqueous solution with ammonium hydroxide: Precipitate compositions and coprecipitation mechanisms
Authors: Packter A. , Panesar K. S. 
Published: January 2007

AbstractMagnesium hydroxoaluminate hydrates were coprecipitated from different mixed metal cation solutions at Mg/Al2 ratios from 1 to 4 by ammonium hydroxide. The coprecipitations were monitored by potentiometric titration and the final precipitate compositions were examined by chemical analysis, X‐ray diffraction, infra‐red spectrophotometry and thermal analysis. The process of coprecipitation was similar to that for coprecipitation with sodium hydroxide but large excess of ammonium hydroxide was required for complete reaction at pHs from about 8 to 10.

At Mg/Al2 = 1, the main phase was probably Mg(H2O)h [Al(OH)4]2;
at Mg/Al2 = 2, the main phase was probably Mg2(H2O)h [Al2(OH)10];
at Mg/Al2 = 4, the main phase was probably (MgOH4) (H2O)h [Al2(OH)10].
Nonstoichiometry in steps on AB crystals (I). General aspects, including bulk imperfections
Authors: Arnold H. 
Published: January 2007

AbstractStarting with a quasichemical treatment, simple model calculations are given for the equilibrium composition in surface steps containing A and B kinks, the amount and ratio of which is varied by changing the adjacent gas composition. In connection with deviations from step stoichiometry, the total amount of kinks increases strongly.A nearest neighbour approximation has been applied to the attachment of A or B atoms at kinks from the gas phase, and also from the bulk by formation of vacancies VA or VB. These processes can be formulated separately for the two elements, taking into account the effective formation of bulk atoms of the other kind (BB or BA).
Comparing investigation of the smectic C and A phases of the di‐n‐alkyl 4,4′‐azoxycinnamates (I). Calorimetric investigations
Authors: Wiegeleben A. , Diele S. , Demus D. 
Published: January 2007

AbstractWe present calorimetric investigations (DSC) of 9 members of the homologous series of the di‐n‐alkyl 4‐4′‐azoxycinnamates. The phase transitions smectic C/A and smectic A/isotropic are characterized by thermodynamic changes which are discussed comparingly. With increasing length of the n‐alkyl chains in the series the clearing temperatures are depressed, the SA regions are diminshed and the character of the phase transitions C/A changes from second order to the direction of first order.
Moisture resistance of polished and coated KCl windows
Authors: Nistor L. C. , Nistor S. V. , Teodorescu V. , Voda M. M. 
Published: January 2007

AbstractThe moisture resistance of ultratransparent KCl grown in a reactive atmosphere was studied on polished KCl samples coated with protective films of BaF2. The lifetime was improved about 4 times compared with uncoated samples. A further improvement was obtained by additional chemical polishing before coating. However, in such a case buckling of the film in a pattern of narrow parallel stripes was observed in an intermediate stage of the humidity test.
On normal kinetics in the case of some refractory and transition metals' crystallization
Authors: Baikov Yu. A. , Chistyakov Yu. D. 
Published: January 2007

AbstractIn given work the crystal growth kinetics connected with some refractory and transition metals is considered. For melts of Fe, Co, Ni, Cr, Zr, Ti, Ag, Cu, and Pb in the vicinity of melting temperatures the solid phase growth is described by means of a fluctuation theory applied for the macro‐systems. By virtue of the “unlimited” and limited spectrum solid state particle concentration fluctuations' theory some effective kinetic coefficients have been estimated in the work. The effective kinetic coefficients are specific in the case of normal crystal growth kinetics. In the case of the crystallization of Fe, Co, Ni, Cr, Zr, Ti, Ag, Cu, and Pb‐melts a comparison between two effective kinetic coefficients (based on the fluctuation theory and so‐called equilibrium growth points density) has been realized. In most cases a satisfactory agreement between the effective kinetic coefficients has been observed.
Undoped semi‐insulating GaAs crystals grown by a modified low pressure LEC method
Authors: Mo P. G. , Fan X. Q. , Zhou Y. D. , Wu J. 
Published: January 2007

AbstractA modified low pressure in‐situ synthesis LEC method of growing undoped SI (semi‐insulating) GaAs crystals has been established. The key points for controlling melt composition and As evaporation during synthesis and growth have been described. Using this novel approach, crystals are able to be grown from the nominal melt composition in the range of 0.491–0.499 As fraction with high reproducibility. Some characteristics of the undoped SI crystals grown by the present work including electrical properties, dislocation density, carbon and EL2 concentrations and thermal annealing effects have been studied.
Lamellar eutectic growth at minimum entropy production
Authors: Wolczyński Waldemar 
Published: January 2007

AbstractA mode of determination of entropy production per unit time for regular eutectic growth is presented. In order to integrate this thermodynamic quantity, both diffusion equation and coefficient of the interplay between curvature of an interface and concentration field are taken into account. The adaptation of the criterion of minimum entropy production allowed to show the equation (growth law) describing the lamellar structure formation under imposed temperature gradient and given growth rate for an alloy under investigation.
Crystal growth and twin formation of gypsum )
Authors: Bartels H. , Follner H. 
Published: January 2007

AbstractTheoretical growth and equilibrium forms of gypsum have been determined by the Fourier transform method. Both are in good agreement with the experimental observations. There are some differences to previous publications which are based on energetic calculations by ionic interaction energies. It is possible to predict five planes of intergrowth. Two of them are wellknown in literature.
The annealing of alkaline‐earth metal polymetaphosphate powders (I). Crystallisation and sintering processes
Authors: Packter A. , Doherty W. O. S. 
Published: January 2007

AbstractAmorphous barium, strontium, calcium and magnesium polymetaphosphate powders (MP2O6)n, n = 20 were prepared by dehydration of the corresponding polymetaphosphate hydrate precipitates. These powders were annealed by different continuous and isothermal heat treatments over the temperature range 450° to 700 °C, the glass transition temperatures Tg to above (Tg + 120) °C. The morphologies at different degrees of crystallisation were studied by scanning electron microscopy. For the main crystallisation process (ten to sixty‐seventy percent crystallisation), the powder particles retained their original pea‐pod form; then after seventy percent crystallisation, these crystallised particles sintered laterally to lozenge‐shaped twin‐hexagonal crystals of lengths 0.5 to 3 μm.Differential thermal analysis confirmed that a markedly exothermic crystallisation process (overall enthalpy changes from about 30 to 45 kJ mol−1) was occurring within the powder particles. Crystallisation rates varied from < 0.005 min−1 at temperatures near Tg to > 0.5 min−1 at higher temperatures; the activation energies for this process varied from 360 to 560 kJ mol−1.The completely annealed crystals were studied by scanning electron microscopy, X‐ray diffraction and further differential thermal analysis to 1000 °C. The X‐ray diffraction d value patterns, the fusion temperatures and the enthalpies of fusion were all in close agreement with the literature values for the corresponding beta alkaline‐earth metal polymetaphosphates prepared by melt crystallisation.
Growth, characterization and fabrication of n‐WSe2 PEC solar cells
Authors: Agarwal M. K. , Rao V. V. 
Published: January 2007

AbstractSingle crystals of n‐WSe2 have been grown by the chemical vapour transport (CVT) technique, using Br2, TeCl4, and SeCl4 as transporters. Crystal lattice parameters have been determined for all the crystals grown above with an X‐ray diffractometer. The composition of the above crystals were examined by energy dispersive analysis of X‐rays (EDAX). Optical and some electrical transport measurements are carried out to judge the semiconducting nature of the as‐grown crystals. Photoelectrochemical (PEC) solar cells were frabricated by using these crystals as photoelectrodes and platinum grid as counter electrode in an aqueous iodine/iodide solution. Some of the PEC cell parameters were determined. The results thus obtained have been discussed in detail.
Growth rate studies on n‐pentadecanoic acid crystals: Reversibility of A′ → B′ transition
Authors: Prasad P. B. V. 
Published: January 2007

Abstractn‐Pentadecanoic acid has A′ → B′ and B′ ⇌ D′ transitions in the crystalline state. Information obtained from the growth rate studies on the crystals of this material is interpreted as an indication of reversibility of A′ → B′ transition.
Small angle neutron scattering in AlCuMg alloys
Authors: Schmidt Ulrike , Ostanevich Juri M. 
Published: January 2007

AbstractThe structure changes proceeding in AlCu 2.1 at.% Mg(x) alloys with magnesium concentration form 0 to 1.2 at.% at room temperature and 100 °C are followed by small‐angle neutron investigation. The results are fitted on different models. The most important result is that with increase of the Mg contents clearly a growth of the thickness opposite to the growth of the growth of the diameter to discern. The results give a good idea of the formation of GPZI(Mg) with the adequate portion of magnesium in the AlCuMg(x)‐alloys and their transition to GPZII(Mg) respectively θ″ (Mg).
DSC characterisation of various phase transitions in mesomorphic benzylidene anilines
Authors: Pisipati V. G. K. M. , Rao N. V. S. , Alapati P. R. 
Published: January 2007

AbstractTo analyse the order of the phase transitions in a number of mesomorphic benzylidene anilines, the DSC (Differential Scanning Calorimetry) method proposed by NAVARD and HAUDIN is used. This method involves the measurement of the ratio (N) of the DSC peak heights H2/H1 for a given transition, performed with two different heating rates (T2/T1). N is a function of the ratio r2/r1(= R) and the magnitude of N provides a simple way to characterize the order of a phase transition.
Ageing effect on dielectric properties of SnO2, Sb2O3, and their mixed thin films
Authors: Kumar J. Siva , Rao K. V. Satyanarayana , Rao U. V. Subba 
Published: January 2007

AbstractThin films of various thicknesses in the form of MIM structures have been prepared from the powders of high purity of SnO2, Sb2O3, and their mixed powders separately by the thermal evaporation technique in a vacuum of 10−5 Torr. The dielectric properties of these oxide thin films have been studied with ageing time and also with frequency at room temperature. The results obtained have shown that the capacitance and loss tangent of the structures initially fall off rapidly and thereafter they attain a constant value even after ageing the capacitors for about 20 days. The rapid fall of capacitance and loss tangent may be due to the rapid decrease in the density of defects due to ageing time. The results thus obtained on SnO2, Sb2O3, and their mixed thin film capacitors are presented and discussed.
Electro‐optical properties of InGaAs layers grown by hydride vapour phase epitaxy
Authors: Attolini G. , Bocchi C. , Fornari R. , Pelosi C. , Oswald J. , Pastrnak J. 
Published: January 2007

AbstractA series of epitaxial layers of the InGaAs alloy were deposited on (001) oriented InP substrates by using hydride VPE technique. The layers were characterized by Double Crystal Diffractometry (DCD), Photoluminescence (PL), Hall effect and Capacitance‐Voltage (C‐V) measurements. The growth parameters and the quality of the grown layers are discussed on the basis of electrical and structural data analysis.
Peculiarities of columnar structure formation in electrodeposited CoW films
Authors: Shadrow V. G. , Boltushkin A. V. , Tochitskii T. A. 
Published: January 2007

AbstractThe microstructure of Co—W films with perpendicular magnetic anisotropy has been investigated. It is shown that the peculiarities of the columnar structure formation and the changes of magnetic and mechanical properties associated with them are accounted for by the electrodeposition conditions and adsorption of the products of electrode reactions at the cathode.
Crystal structure and magnetic properties of some Mn2Sb‐based alloys
Authors: Ryzhkovskii V. M. , Zhigadlo N. D. , Pashkovskii I. L. 
Published: January 2007

AbstractThe results of the investigation of structural and magnetic properties of the Mn2(Ni)Sb, Mn2(Cr,Cu)Sb Mn2(Ti,Zn)Sb alloys are reported. The solubility limits of the elements substituting Mn in the Mn2Sb matrix, keeping the crystal structure of the Cu2Sb(C38)‐type, are established and the lattice parameters temperatures of magnetic phase transitions, specific magnetization of the materials are determined. The influence of thermal treatment and thermal cycling on the magnetic properties of the alloys, which is interpreted by the quantitative redistribution, depending on temperature, of the amount of the main δ‐phase (C38) in the samples, with the phase composition changing, and that of an additional nickel‐arsenide ϵ‐phase has been found.
Effective kinetic coefficients for some binary metallic alloys within the small and finite supercooling region
Authors: Baikov Yu. A. , Chistyakov Yu. D. 
Published: January 2007

AbstractThe normal crystallization kineties concerning the base of In, Rb, Ga some binary metallic melts either within the small supercoolings (Δ T ≦ 1 K) or finite ones (ΔT ≦ 20 ÷ 60 K) has been considered. When crystallizing the binary alloys: In + 2.3 at.% Pb; Rb + 10 at.% K; Ga + 2 at.% Sn; Ga + (2; 4; 8) at.% In; Ga + (0.5; 3.5) at.% Zn; Ga + (5; 8; 10) at.% Zn very dilute binary solid solutions are supposed to be formed. The solid solutions have the B‐component distribution coefficients which are either much less or less compared with unit, i.e. kB ≦ 1, kB < 1 in all the layers of diphase transition region separating the melt from the crystalline phase. By virtue of fluctuation theory of normal crystal growth within the small and finite supercoolings' region for the above‐mentioned binary metallic melt some effective kinetic coefficients have been calculated. A good agreement between theoretical effective kinetic coefficients and available experimental ones in the case of given binary systems has been established.
The influence of the Mg content and the quenching conditions on the decomposition kinetics of AlZnMg alloys
Authors: Wolter R. , Fabian H.‐G. , Czurratis P. , Kroggel R. 
Published: January 2007

AbstractBy means of resistivity measurements, TEM and microhardness measurements the decomposition kinetics of A1‐3 at.% Zn‐1.5 at.% Mg and A1‐4.5 at.% Zn‐x at.% Mg (x = 0.2; 0.5; 1.0; 1.5; 2.25; 3.0) were investigated. For Ta < Ta, crit < Th (Th: temperature of the rapid homogenous nucleation) in A1‐3 at.% Zn‐1.5 at.% Mg and A1‐4.5 at.% Zn‐x at.% Mg (x = 1.0; 1.5; 2.25; 3.0) an inversion of the decomposition kinetics for Tq > Tinv: (Tinv: inversion temperature) was established. This result can be explained with reference to the binding of excess vacancies in dislocation loops.Proceeding from the discrepancy between the experimentally estimated concentrations of vacancies bound in dislocation loops and the concentrations of free vacancies at Tq, calculated by means of the Lomer equation, a model is proposed, which explains the high vacancy concentration of the loops. In terms of this model the values of the migration energy, obtained for A1‐3 at.% Zn — 1.5 at.% Mg in the Ta‐range 23 °C ≦ Ta ≦ 100 °C, and the shift of the inversion temperatures Tinv towards higher values with increasing Ta are interpreted. The same applies to the influence of the Mg content on the decomposition kinetics in A1‐4.5 at.% Zn‐x at.% Mg alloys.
Minimum undercooling condition as a particular case of the criterion of minimum entropy production
Authors: Wołczyński Waldemar 
Published: January 2007

AbstractThe attempt to compare the diffusional‐thermal model based on the criterion of minimum entropy production to diffusional one based on the condition of minimum undercooling has been presented for regular eutectic growth. Finally, the general relationship describing lamellar structure formation is to be reduced to another one proposed by Jackson and Hunt's theory. This reduction has been in great part obtained. However, it remain some equivalent terms, which are not identical. It is probably produced by some imperfections of Jackson and Hunt's model, as well as any other adversities, e.g., some different assumptions in both compared models. The reduction of the criterion of minimum entropy production to the condition of minimum undercooling has also been suggested.
Etching of silicon trenches in CF4 plasma using photoresist/aluminium masks
Authors: Glück B. , Höppner W. 
Published: January 2007

AbstractThe reactive ion etch process (RIE) of silicon in a CF4/O2 gas mixture is described. The dependence of the etch rate and the surface quality on used mask material (photoresist, aluminium) is studied.A silicon etch rate of about 1.5 times higher than with resist mask is reached using aluminium as mask material. The free etched surfaces are very rough due to micromasking effects during the etch process. Using a phtoresist mask the surfaces remain clean. The silicon etch depth depends on the thickness of the mask.
Crystal structure analysis and refinement of Kalabsha kaolinite (Al2Si2O5(OH)4)
Authors: El‐Sayed Karimat , Heiba Z. K. , Abdel‐Rahman A. M. 
Published: January 2007

AbstractThe crystal structure of the kaolinite mineral from Kalabsha, Aswan, Egypt, has been investigated with a two‐step procedure of the X‐ray powder pattern‐fitting. The unit cell is found to be triclinic, P1, a = 5.1577(15), b = 8.9417(23), c = 7.3967(40) Å, α = 91.672(5)°, β = 104.860(2) and γ = 89.898(2)°. The refinements of the non‐hydrogen atomic positions showed a reliability factors RWB = 0.037 and RB = 0.0417. The average rotation angle in the tetrahedral layer in 10°.
X‐ray studies of binary mixtures of smectics A1 with a nematic gap and reentrant nematic phase
Authors: Ważyńska B. , Przedmoj̇ski J. 
Published: January 2007

AbstractBinary mixture of 80BCAB—10TPCHB system are investigated. It is shown that the dimerization of 80BCAB compound in the matrix of 10TPCHB takes place as it was in 7CBB—10XPCHB systems. The generalized conclusion is drawn that such a behaviour is common for homologous series the members of which with shorter aliphatic chains yield the smectic A1 phase and those with longer chains the Ad one.
Crystal and molecular structure of 2‐diazo‐5‐phenyl‐cyclohexan‐1,3‐dione
Authors: Ramm M. , Schulz B. , Thurner J.‐U. , Ulbricht M. 
Published: January 2007

AbstractMr= 214.24, monoclinic space group P 21,a= 10.964(2),b= 5.870(2),c= 8.574(2) Å, β = 98.09(2)°,V= 546(1) Å3,Z= 2,Dx= 1.302 Mg m−3,F(000) = 224, λ (MoKα) = 0.71069 Å, μ = 0.8 mm−1. The crystal structure was determined by direct methods and refined by least‐squares procedure to the discrepancy factorR= 0.034.Mr= 214.24, monokline Raumgruppe P 21,a= 10.964(2),b= 5.870(2),c= 8.574(2) Å, β = 98.09(2)°,V= 546(1) Å3,Z= 2,Dx= 1.302 Mg m−3,F(000) = 224, λ(MoKα) = 0.71069 Å, μ = 0.8 mm−1.
The influence of the direct quench and indirect quench to Ta > Th on the decomposition behaviour of an Al‐2 at.% Zn‐1 at.% Mg alloy
Authors: Wolter R. , Fabian H.‐G. , Czurratis P. , Kroggel R. 
Published: January 2007

AbstractThe decomposition behaviour of an Al‐2.0 at.% Zn‐1.0 at.% Mg alloy after direct quench (DQ) and indirect quench (IQ:T = 23 °C, t) to the ageing temperature T = 160 °C (above the temperature of the rapid homogeneous nucleation, Th) was investigated by means of TEM and isothermal resistivity measurements. The precipitation density of the η‐particles yields a maximum value at pre‐ageing times about 10 min at T = 23 °C. To clear up the reason for that phenomenon a loop‐formation and clustering model was introduced.
Life time measurements of charge carriers in layer MoSexTe2−x (0 ≦ x ≦ 2) PEC solar cells
Authors: Agarwal M. K. , Patel P. D. , Joshi R. M. , Rao V. V. 
Published: January 2007

AbstractLayer type MoSexTe2−x (0 ≦ x ≦ 2) are grown by chemical vapour transport technique. The photoelectrochemical (PEC) solar cells are fabricated using the grown single crystals as photoelectrodes and platinum grid as counter electrode. The life time measurement of charge carries were carried out using pulse light from a stroboscopic source. The variation of life time with temperature and composition have been studied. The results thus obtained have been concluded.
Coefficient of volume expansion and thermoacoustic parameters in certain alkoxy benzylidene butylanilines — IB
Authors: Venkatacharyulu P. , Prasad K. S. R. , Kasturi A. , Prasad N. V. L. N. , Rao J. V. 
Published: January 2007

AbstractUsing the coefficient of volume expansion certain thermoacoustic parameters like isobaric (K), isothermal (K″), isochoric (K″) acoustic parameters, free volume (Va/V) and two new dimensionless acoustic parameters A* and B* are estimated in certain alkoxy benzylidene butylanilines, in their isotropic‐ and mesophases as well as at and in the immediate vicinity of the phase transition temperatures following the method which was suggested by Sharma, for non‐mesomorphic systems.