bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silicon Epitaxial Layers with Non‐Uniform Doping Profiles (I). The Model Parameters' Adjustment
Authors: Halaj J. 
Published: January 2007

AbstractThe non‐uniform doping profiles may prove useful for some semiconductor devices instead of the uniform ones. In the paper the doping mechanism of silicon epitaxial layers in the SiCl4H2PH3 system is investigated. The epitaxial doping profile simulation program is developed based on the Wong‐Reif trapping model and taking into account also the difference between dopant profile and the charge carrier profile. The three unknown parameters of the Wong‐Reif model are found with the aid of the simulation program.
Synthesis and Characterization of the Levyne‐like Structure SAPO‐35, Prepared with Cyclohexylamine as Templating Agent
Authors: Lohse U. , Vogt F. , Richter‐Mendau J. 
Published: January 2007

AbstractThe microporous aluminophosphate SAPO‐35 with the levyne‐like structure was prepared hitherto only with quinuclidine as templating agent. In this paper it is shown that also cyclohexylamine can be used for the synthesis of SAPO‐35. The samples were characterized by X‐ray diffraction, thermal analysis, adsorption isotherms, and micrographs. These investigations confirm the few data reported on SAPO‐35 and give further informations. The number of acid sites (Brönstedt centres) was determined from the differential molar heat of chemisorption of NH3 to three per unit cell.
Mixed Chalcopyrites as Useful Solar Cell Materials
Authors: Samanta L. K. , Ghosh D. K. , Ghosh P. S. , Chatterjee S. 
Published: January 2007

AbstractI1n view of the present global energy crisis the advent of the ternary chalcopyrites with some important useful properties stimulate us to study these compounds together with their mixed versions with a view to find their suitability as efficient solar cell materials. We finally selected out a few promising materials, as some of them have desirable characteristics and satisfy the stringent requirements for photovoltaic energy conversion.
The Crystal and Molecular Structure of Mesogenic Malonates
Authors: Körner H. , Zugenmaier P. 
Published: January 2007

AbstractThe crystal and molecular structures of diethylene‐6‐[4‐(4′‐nitrophenylazo)phenoxy]dodecylmalonate (12 PhNO2) and ‐propylmalonate (3 PhNO2) were determined with CuKα to a = 19.235(5) Å, b = 7.620(1) Å, c = 22.400(4) Å; α = 90°, β = 103.27(1)°, γ = 90°; space group P21/c for 12 PhNO2 and a = 6.797 (6) Å, b = 7.756 (8) Å, c = 22.74(2) Å; α = 81.48(7)°, β = 88.29(7)°, γ = 68.10(9)°; space group P1 for 3 PhNO2. Refinement with 1130 observed reflections (> 3σ) for 12 PhNO2 and 1615 for 3 PhNO2 leads to R (12 PhNO2) = 5.8% and R(3 PhNO2) = 4.4%.The molecular conformation in the crystalline state is the most extended trans conformation for both compounds. On rapidly cooling from the isotropic melt, 12 PhNO2 shows a smectic A‐phase. In agreement with prior investigations on polar mesogens, the molecules arrange in an antiparallel packing. The azo‐mesogen is nearly coplanar with the alkoxy spacer up to the branching atom. The low molecular weight malonates investigated may serve as model compounds for side‐group liquid crystalline polymers.
Study of film crystallization kinetics initial stage by Monte Carlo simulation
Authors: Aleksandrov L. N. , Bochkova R. V. , Kiselev G. B. , Entin I. A. 
Published: January 2007

AbstractThe Monte Carlo Simulation has been used for studying the initial stage characteristics of film crystallization during the layer‐by‐layer film growth by two‐dimensional nucleation. It is shown that the non‐monotonous changes of the growing film perimeter and mass correspond to the reflection intensity oscillation from the growth surface. The observed changes of the overgrowing part of the surface are in agreement with the probability‐statistical calculations. The vizualization of surface relief changes during the growth process under different conditions has been provided.
Influence of size on the supercooling in the crystallization of small particles in Bismuth island films
Authors: Gladkikh N. T. , Larin V. I. , Maiboroda S. A. 
Published: January 2007

AbstractThere has been measured the crystallization temperature of supercooled Bi particles versus their size in the 3–100 nm range in island films on amorphous carbon substrates. Crystallization temperature is found to decrease with particle size decreasing and the supercooling vanishes for particles of 2–3 nm in diameter. The results obtained are analyzed in the frame of the classic theory of crystallization.
DCXS and RHEED characterization of effectiveness of annealing implanted Si crystals by using pulsed UV excimer laser and sample scanning technique
Authors: Auleytner J. , Kozankiewicz B. , Regiński K. 
Published: January 2007

AbstractIn the experiment (111) oriented silicon plates were implanted with 80 keV Ge ions (dose 5 × 1015 cm−2) and with 150 keV Kr ions (dose 5 × 1015 cm−2). Then the samples were annealed with the pulsed excimer laser by using the sample scanning technique. The effectiveness of the annealing has been analyzed by means of double crystal X‐ray spectrometry (DCXS) and reflection high energy electron diffraction (RHEED). The results of the experiment show that the applied technique of annealing considerably improves the perfection of the structure of the implanted silicon crystals.
Elastic properties of the dithionates Na2S2O6 · 2 H2O, K2S2O6, Rb2S2O6, CaS2O6 · 4H2O and SrS2O6 · 4 H2O
Authors: Haussühl S. 
Published: January 2007

AbstractSingle crystals of the title compounds having optical quality and dimensions of several cm were grown from aqueous solutions. The elastic and thermoelastic constants were determined from ultrasonic resonance frequencies of thick plates. The true point symmetry of K2S2O6 and Rb2S2O6, which is screened by a hexagonal hypermorphy, could be clearly revealed to be trigonal (32) by the existence of the elastic constant c14. In the case of CaS2O6 · 4H2O and SrS2O6 · 4H2O the constant c14 of the specimens appeared too small to confirm the trigonal symmetry group required from electrooptic and non‐linear optic effects unambiguously.The isotypy of K2S2O2 and Rb2S2O6 as well as that of CaS2O6 · 4H2O and SrS2O6 · 4H2O is confirmed by their elastic behaviour. The mean elastic stiffness of dithionates is closely related to that of the corresponding sulphates. In the vicinity of the second‐order phase transition of K2S2O6 near 235 K weak anomalies of the temperature derivatives of the longitudinal elastic stiffnesses are observed.
The superposition of the lattice radiation and reflectivity spectra of MoO3 and PbMoO4 crystals
Authors: Syrbu N. N. , Stamov I. G. 
Published: January 2007

AbstractThe Raman scattering of MoO3 at 300 and 77 K and the infrared reflectivity spectra of MoO3 at 300 K have been investigated in different scattering geometries. The Raman spectra of PbMoO4 crystals at 77 K have been investigated also. The reflectivity spectra of MoO3 crystals were calculated for E ∥ c and E ∥ a. The phonon parameters and the effective ionic charges of anions and cations for MoO3 and PbMoO4 crystals are determined. The diagrams of the splitting of the vibrational levels by the Davydov resonance and by the factor group interactions have been determined. It is shown that the lattice radiation of crystals which have a number of vibrational oscillators (MoO3, PbMoO4) begins at low energy vibrational modes and at low values of the damping parameters.
Growth of GaAs from Ga solution under reduced gravity during the D2‐mission
Authors: Danilewsky A. N. , Nagel G. , Benz K. W. 
Published: January 2007

AbstractTellurium‐doped GaAs was grown under reduced gravity during the Second German Spacelab‐Mission D2. The growth experiment MD‐ELI‐TRABE is described and first results are presented.
Fast growth of optical nonlinear crystals of 4‐aminobenzophenone from the melt. A candidate for blue light output
Authors: Pan S. K. 
Published: January 2007

AbstractThe Kyropoulos method was used to grow non‐linear optical (NLO) organic crystals of 4‐aminobenzophenone (ABP) from the melt. Growth conditions were discussed. The entropy of fusion of ABP material is 6.75. The crystals had a large effect of frequency doubling.
Growth of lanthanum heptamolybdate crystals by gel technique
Authors: Bhat Sushma , Kotru P. N. 
Published: January 2007

AbstractThe growth of single crystals of lanthanum heptamolybdate is achieved by allowing controlled diffusion of La ions through silica gel using the system La(NO3)3MoO3NH4OHHNO3–Na2SiO3. The reaction mechanism leading to the growth is reported. Mechanism of crystallization of La heptamolybdate is discussed. Formation of Liesegang rings consisting of La heptamolybdate crystals in the system is reported. It is observed that concentration programming and seeded growth enhances the size of crystals. The crystals grown in the system are single crystal platelets exhibiting squarish or octagonal facets. Some crystals exhibit a spherulitic morphology.
Simulation of dopant zone‐leveling for variable distribution coefficient in KCl: EuCl2 system
Authors: Cywiński R. , Damm J. Z. 
Published: January 2007

AbstractExperimental data of Eu2+ distribution in EuCl2‐doped KCl ingots are analyzed. After settling the relation between variable distribution coefficient and the dopant concentration in the melt, the simulation of the dopant zone‐leveling for various molten zone widths is performed. It is shown that owing to the decrease of the distribution coefficient caused by increasing dopant concentration in the molten zone, the number of the zone passes after which the dopant concentration levels off undergoes significant reduction.
Crystal and molecular structure of 2.2′‐dihydroxyazobenzene
Authors: Schilde U. , Hefele H. , Ludwig E. , Uhlemann E. 
Published: January 2007

AbstractC12H10N2O2; monoclinic, space group P1 21/c 1 (Z = 2), 826 observed independent reflexions, R = 0.043; lattice dimensions at 25 °C, a = 975.8(3) pm, b = 466.8(1) pm, c = 1186.8(2) pm, β = 108.51(1)°.
A possible new approach to the better understanding of crystallization kinetics
Authors: Stávek J. , Ulrich J. 
Published: January 2007

AbstractLiterature data dealing with the structure of solutions, solubility of tiny particles, and the organization of small colloidal particles in solutions were summarized to support the evidence that the growth units in the crystallization by precipitation are identical with clusters or primary particles. These growth units may self‐organize themselves in a kind of a three‐dimensional network surrounding the growing crystals or secondary particles. This colloidal concept was used to explain qualitatively some experimental facts observed in the controlled double jet precipitation of sparingly soluble salts.
ASL model for prediction of CSD in a continuous crystallizer
Authors: Dey Avijit , Gupta Bhaskar Sen 
Published: January 2007

AbstractA Monte Carlo simulation scheme is proposed for crystal size distribution (CSD) in a continuous crystallizer for size dependent growth rate. Crystal growth rates are described by Abegg, Stevens, and Larson (ASL) model. The proposed model is used to predict CSD from potassium carbonate crystallizer. The agreement between theory and available data confirms the validity of the model.
The effect of the in‐situ sublimation in the growth of HgI2 platelets from vapour
Authors: Serrano M. D. , Santos M. T. , Diéguez E. , Toubektsis S. N. , Daviti M. F. , Polychroniadis E. K. 
Published: January 2007

AbstractThe Quality of HgI2 platelets grown from the vapour phase has been studied, varying different growth parameters, i.e. starting material, addition of polyethylene, source/crystallisation temperature, in‐situ sublimation. It has been found that the in‐situ sublimation at high temperature is the essential factor for the production of HgI2 platelets. This in‐situ sublimation was made in the same growth ampoule at temperatures over 200 °C and prior to the growth process. All the other growth parameters studied in this work influenced the quality of the platelets although they did not affect their production. Finally, the grown platelets have been characterised by optical observation and by differential scanning calorimetry.
Solidification behaviour of binary organic eutectic alloys
Authors: Rai U. S. , Shekhar H. 
Published: January 2007

AbstractThe phase diagrams of binary organic faceted‐faceted systems of p‐dibromobenzene with acenaphthene, p‐chloronitrobenzene and acetanilide show the formation of a simple eutectic with 0.53, 0.61, and 0.64 mole fraction of p‐dibromobenzene, respectively. Crystallization data, determined by the capillary method, suggest that the eutectics of p‐dibromobenzene with acenaphthene and p‐chloronitrobenzene solidify with alternate nucleation mechanism and the crystallization of the eutectic of p‐dibromobenzene‐acetanilide system takes place by the side‐by‐side growth of the phases involved. With a view to throw light on the thermodynamic behaviour of eutectic alloys of non‐metals, heats of fusion of their transparent organic analogues and their eutectics were determined, and using these values different thermodynamic parameters were calculated. The microstructures of the eutectics show their typical characteristic features.
Anomalous dispersion correction terms of As and Sb
Authors: Saravanan R. , Mohanlal S. K. 
Published: January 2007

AbstractIn our earlier paper (Saravanan et al.), we have evaluated the imaginary part of the anomalous disperison correction term f″ of Ga and In from the measured structure factors of GaP and InP, where one of te atoms (P) is relatively lighter than the other. In the present work the f″ values of As and Sb have been evaluated using the experimental structure factors of GaAs and InSb (where both the atoms are equally heavy) adopting the same principle used in our earlier work. Though both atoms in GaAs and InSb are heavy, this method gives satisfactory results.
To the new theory of crystal strength
Authors: Vlasov A. D. 
Published: January 2007

AbstractThe main conceptions of the non‐dislocation theory of crystal strength have been proposed. These are the thermal stress, the temperature coefficient of thermal stress, and the initial microstrain ϵin at which the thermal stresses start. These conceptions made possible an explanation of the crystal lattice mechanical instability that is well known from strength tests. A new simple form of Morse potential, a relation for the thermal stress, and a way to find the temperature coefficient in this relation have been advanced. Some measurements of very high and of common practice strengths of crystals were compared with theoretical suppositions and calculations.
Dielectric studies on sodium fluoroantimonate single crystals
Authors: Charles J. Benet , Gnanam F. D. 
Published: January 2007

AbstractDielectric properties of grown single crystals of Na2SbF5 and Na3Sb2F9 have been carried out. The values of the dielectric constant of Na2SbF5 and Na3Sb2F9 are about 24.1 and 14.3, respectively, at temperatures from 30 °C to 250 °C and 225 °C for 100 kHz.
Debye characteristic temperature of some silver‐base binary alloys
Authors: Bhikshamaiah G. , Sadanandam J. , Suryanarayana S. V. 
Published: January 2007

AbstractThe Debye characteristic temperature (θ) of eight silver base binary alloys in the cubic phase having various compositions have been calculated making use of four different averaging methods from the data on elastic constants. The values of θ are also evaluated from series expansion method. The results obtained were examined in terms of solute concentration, reciprocal of the lattice parameter, mass, electron to atom ratio, and elastic anisotropy. Important conclusions are made.
On the nature of growth hillocks on sodium chlorate crystals
Authors: Szurgot Jadwiga , Szurgot Marian 
Published: January 2007

AbstractOptical examination of as‐grown {100} surfaces of sodium chlorate crystals grown from aqueous solution revealed the presence of elliptical growth hillocks. The hillocks were present on both enantiomorphous forms and originated from dislocations, inclusions, and microcrystals attached to the growing surface. The value of the surface entropy factor equal to 4.55 at 313 K suggests that crystals grow via/or with the participation of dislocation mechanism, and the hillocks are dislocation growth centers. Compound mechanism controlled growth of some crystals because edge nucleation and dislocation centers operated simultaneously on the same surfaces.
Structure of 3β, 20‐diacetoxy‐16α‐methyl‐allopregn‐17(20)‐ene
Authors: Singh Attar , Gupta Vivek K. , Rajnikant  , Goswami K. N. 
Published: January 2007

AbstractC26H40O4, a steroid (3β, 20‐diacetoxy‐16α‐methyl‐allopregn‐17(20)‐ene) crystallizes in the orthorhombic space group P212121. The unit cell parameters are a = 10.745(2), b = 11.190(3), c = 20.208(1) Å. The structure has been elucidated by direct methods. The final residual index (R) converges to 0.042, weighted residual index (wR) being 0.044. Rings A and B adopt normal chair conformation whereas ring C is found to be very close to chair and ring D exists in 14α‐envelope conformation. The ring junctions A/B, B/C, C/D are trans‐fused about the bonds C5–C10, C8–C9 and C123–C14, respectively.
Positron lifetime study in BaTiO3 ceramics with different Ba/Ti ratios
Authors: Tang C. Q. 
Published: January 2007

AbstractThe positron lifetime spectra in 0.25 at.% La‐doped BaTiO3 with different Ba/Ti ratios have been measured at room temperature. It was found from the experiments that with deviating from exact stoichiometry the positron lifetime τ2 decreases and the intensity I2 increases for Ba/Ti ratio smaller than stoichiometric and they have more significantly similar changes for Ba/Ti ratio larger than stoichiometric. The non‐monotonic dependence of positron lifetime parameters on Ba/Ti ratio is regarded as that the τ2 component is contributed together by positrons annihilating at the grain boundaries and Ba vacancies and/or Ti vacancies, and small deviations from exact stoichiometry would be expected to increase the concentration of defects such as Ba vacancies for Ba/Ti < and Ti vacancies for Ba/Ti > 1.
Liquid phase epitaxial growth and characterization of thin In1−xGaxAsyP1–y layers lattice‐matched to InP
Authors: Becher S. , Gottschalch V. , Wagner G. , Schwabe R. , Staehli J. 
Published: January 2007

AbstractGrowth studies enabled the deposition of In0.71Ga0.29As0.68P0.32 single quantum well structures with InP or In0.88Ga0.12As0.26P0.74 confinement layers lattice‐matched to (001) InP by liquid phase epitaxy (LPE). Well widths in the order of 50–100 Å have been achieved using a conventional step cooling technique. The physical characterization has demonstrated the capability of the employed method to produce multilayered heterostructures which display confined particle states; quantum mechanically induced blue‐shifts of the low temperature PL‐emission up to 125 meV were measured. A remarkable reduction of the FWHM values of the shifted PL peaks was attained by optimization of the growth conditions.
Investigation of the formation and growth processes of silicon carbide monocrystals
Authors: Lilov S. K. 
Published: January 2007

AbstractThe formation and growth processes of SiC monocrystals from vapour phase by sublimation method have been investigated. It is shown that the peaks of the evaporation and growth whiskers are the centres of SiC monocrystals formation. One of the mechanisms of development of the whisker into SiC platelet is established. It is shown that on the naturally mirror like crystal face either the edge of the crystal or the screw dislocation, situated on the crystal edge, is the source of the steps. On the stepped crystal face the root of the crystal is the source of the steps.
Synthesis and X‐ray structure studies of complex [Cu(o‐phenanthroline)2 (saccharin)] · (saccharin) · 2 H2O
Authors: Yugeng Zhang , Jianmin Li , Jing Wei , Xingtao Wu , Shaowu Du 
Published: January 2007

AbstractThe title compound has been synthesized and its crystal structure determined at room temperature, Mr = 824.34, triclinic, space group P–1(2), a = 13.622(4), b = 13.770(4), c = 11.167(3) Å; α = 104.83(2), β = 110.01(2), γ = 62.04(2) degree; U = 1727.0(9) Å3, Z = 2, Dcalc = 1.59 g/cm3. The final R is 0.066 for 3299 independent observed reflections with I ≧ 3σ(I). The crystal structure consists of repeated [Cu(o‐phen)2(sac)]+ cations, non‐coordinated saccharin anion and two lattice water. And the central ion Cu2+ forms a trigonal‐bipyramidal stereochemistry.
Thermoelectric power of indium sesquisulphide single crystals
Authors: Nassary M. M. 
Published: January 2007

AbstractThe investigation covers a temperature range from 200 to 450 K. Thermoelectric power measurements of In2S3 crystals showed that all samples under investigation have a positive TEP in all temperature ranges, indicating n‐type conductivity for In2S3 crystals. The ratio of the electron and hole mobilities is μn/μp = 4.71. The effective mass of electrons m is found to be 0.00008 × 10−31 kg. The obtained effective masses of holes m = 1.893 × 10−31 kg. The diffusion coefficient for both carriers (electrons and holes) is evaluated to be 84.71 cm2/s and 17.985 cm2/s respectively. The mean free time between collision is estimated to be τn = 1.7 × 10−20s, and τp = 8.5 × 10−17s. The estimated diffusion length for electrons is found to be Ln = 1.2 × 10−9 cm and Lp = 3.9 × 10−8 cm.
Gas etching of GaAs monocrystalline substrates in the presence of Ga‐ and In sources
Authors: Popov A. S. , Hitova L. , Atanasova R. K. , Nikolova S. L. 
Published: January 2007

AbstractA special case of gas etching of GaAs substrates in the process of VPE in the presence of (Ga + In) source was investigated. The dependence of the etching rate on the source and the substrate temperature, and the AsCl3 content in the gas flow was studied.
On voids in InxGa1−xSb crystals grown by an ultrasonic‐ vibration‐introduced Czochralski method
Authors: Kumagawa Masashi , Tsuruta Takuya , Nishida Naoki , Ohtsuki Jun , Takahashi Katsumi , Adachi Satoshi , Hayakawa Yasuhiro 
Published: January 2007

AbstractThe shape and size of voids, and the grown region surrounding a large void were investigated in InxGa1–xSb crystals, which were pulled under the introduction of ultrasonic vibrations into the source melt by using a modified Czochralski apparatus. The presence of voids in crystals resulted from (1) atmosphere gas was confined beneath the growth interface of a seed crystal during the seeding procedure, and (2) many bubbles–generated by the cavitation effect due to ultrasonic vibrations–were caught in the growing crystal. Voids were circular, deformed trapezoid, and complex in shape, and were in a range of 20 μm to 3 mm in size. Even in case of a void with the diameter as large as 2 mm, the grown region surrounding it was in the single crystalline state. In this interesting region, the microscopic variation of In concentration and the abrupt change of growth rate were observed.
Growth kinetics of RF‐sputtered nickel films in the beginning stages
Authors: Mikhailov I. F. , Fomina L. P. , Borisova S. S. , Babenko I. N. , Melnik N. N. , Pudonin F. A. 
Published: January 2007

AbstractBy the analysis of X‐ray reflectivity angle dependence the existence of a characteristic nucleus height h in the island stage of nickel growth have been found. As the condensation time τ rises, the value of h increases according to a linear law, and the portion of substrate surface occupied by nuclei is described by a curve with saturation. The formation latent period of the fraction with preferential size h is extremely small, that, in principle, allows to produce smooth surfaces, even if the effective thickness is only about several atomic layers. The kinetic characteristics are identical both at growing on monocrystalline silicon and amorphous SiOx substrates.