bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron microscopy of γ‐irradiated polyethylene
Authors: Bercia R. , Tirnovan M. , Bercia C. , Popescu‐Pogrion N. 
Published: March 2006

AbstractIn this paper, we have studied the structure and the phase transformations in thin films (obtained by evaporation from γ‐irradiated polyethylene bulks—ageing polymer) before and after laser irradiation. We made a comparison between the following samples: A—thin films obtained from γ‐irradiated polyethylene bulk and not subjected to laser irradiation; B—thin films obtained from γ‐irradiated polyethylene bulk and subjected to laser irradiation. We have revealed many modifications in the dielectric and structural properties of the thin films, depending on the dose, dose rate and the time of laser irradiation (in the case of samples B). The thickness of all deposited films was 90 nm. The samples (non‐irradiated or irradiated) were analysed by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), in combination with selected area electron diffraction (SAED). We have also presented the structure of non‐aged and non‐irradiated thin polyethylene films (control polyethylene film), in which we observed a particularly puzzling phase between an incipient spherulitic phase and a fine structure of the spherulitic phase (specifically for thin PE films structure). After γ‐ and laser irradiations, we observed a strong modification of the structure. The spherulitic phase was transformed. We observed large, amorphous, transparent crystals containing many defects, carbon precipitates, the beginning of crystallisation revealed by electron diffraction, treeing and breakdown figures (usually after laser irradiation). Copyright © 2006 John Wiley & Sons, Ltd.
Fe3C nanopowder synthesized by laser pyrolysis and its annealing behaviour
Authors: David B. , Schneeweiss O. , Pizúrová N. , Klementová M. , Bezdička P. , Alexandrescu R. , Dumitrache F. , Morjan I. 
Published: March 2006

AbstractWe describe the Fe3C‐based nanopowder obtained through the laser‐induced pyrolysis of the gas mixture of Fe(CO)5 and C2H4. This ferromagnetic nanopowder was characterized by XRD, HRTEM and magnetic measurements. Aggregated core‐shell nanoparticles were identified in the nanopowder; Fe3C cores were coated with pyrolytic carbon. The mean coherence domain size estimated by the Scherrer formula was 18 nm. Basic magnetic characteristics were measured at 20 °C: HC = 42.0 kA m−1; σR = 31.2 A m2 kg−1; σS = 95.7 A m2 kg−1 (at 1200 kA m−1). The Curie temperature TC was 227 °C. Thermally induced phase transformations are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
CONFIT: Mössbauer spectra fitting program
Authors: Žák Tomáš , Jirásková Yvonna 
Published: March 2006

AbstractProgram package CONFIT enables a complex processing of 57Fe and 119mSn Mössbauer spectra. The mouse drag‐and‐drop technique is used to set up the background and parameters of the individual spectral components according to the structural model supposed. An original method has been applied: a nonlinear least‐squares procedure with the Fast Fourier Transform (FFT) technique. A combination with improved matrix formalism can create various physical models to analyze the measured experimental data in a proper way. The hyperfine field distribution(s) and also quadrupole splitting distribution(s) with Gaussian profile can be applied, besides discrete components. The finite sample thickness can be included in terms of transmission integral and a dependence of the spectral line‐width on its position with respect to the spectrum center is described by an additional parameter. This fitting procedure is suitable for Mössbauer spectra taken in the transmission and in the back‐scattering geometry (including γ‐ray and conversion electrons) and it can be successfully applied for analyzing the emission Mössbauer spectra. The transmission Mössbauer spectra yield information concerning the bulk microstructure, the back‐scattering geometry is used for surface studies and the emission Mössbauer spectra yield information from grain boundaries or interface regions. The CONFIT is user friendly, fast and applicable for complicated Mössbauer spectra. Copyright © 2006 John Wiley & Sons, Ltd.
RBS and AFM study of Ag and Au diffusion into PET foils influenced by plasma treatment
Authors: Macková Anna , Švorčík Václav , Strýhal Zdeněk , Pavlík Jaroslav 
Published: March 2006

AbstractMetallization of polymers is essential for their application in microelectronic elements and photonics devices. We performed a study of the diffusion of Ag and Au atoms in polyethyleneterephtalate (PET). Thin metal layers were deposited using the diode‐sputtering technique on polymer foils at room temperature. Simultaneous post‐deposition annealing and plasma treatment was used to induce metal/polymer intermixing. Concentration profiles of diffused metals were determined by Rutherford backscattering spectrometry (RBS) and diffusion coefficients were extracted. The influence of the plasma treatment on the surface morphology was studied using atomic force microscopy (AFM). Ag atoms exhibit deeper penetration into polymer structures after Ar plasma treatment than after Ar + O2 plasma treatment. AFM measurements show more significant changes of surface roughness (increased roughness and porosity) of Ag on PET surfaces caused by the Ar + O2 plasma treatment compared to Au surfaces. In the case of very rough surfaces, a decrease of metal diffusivity is observed probably owing to a reduction of surface concentration. The metal mobility is strongly influenced by temperature, which is increased either by direct heating of the sample holder or indirectly by plasma discharge. Copyright © 2006 John Wiley & Sons, Ltd.
Changes in austenitic steel surface induced by thermal and implantation treatments studied by Mössbauer spectroscopy
Authors: Jirásková Yvonna , Schneeweiss Oldřich , Blawert Carsten 
Published: March 2006

AbstractThe surface properties of austenitic (fcc) stainless steel samples in the as‐prepared and implanted states were studied. The surface modification was done by plasma immersion ion implantation in methane. This process, done at a temperature of 400 °C in a short time of 3 h, facilitates the enrichment of the steel surface by a higher carbon content. It reaches about 7 at% C in the top surface layers (∼500 nm) and decreases to the nominal value at approximately 10 µm.The thermal annealing treatments of the as‐prepared and implanted samples, done at temperatures of 300–500 °C and in time steps of 2–4–8–16–32 h, yielded changes in the elemental distribution and phase composition, which could be followed in the top surface layers of approximately 300 nm using conversion electron Mössbauer spectroscopy (CEMS) and for a surface depth down to 30 µm, by γ‐ray Mössbauer spectroscopy in the scattering geometry (γ‐BMS). Complementary results were obtained from glancing‐angle X‐ray diffraction. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of enamel ageing on mechanical properties and phase composition of the steel–enamel system
Authors: Barcova K. , Zboril R. , Mashlan M. , Jiraskova Y. , Filip J. , Lunacek J. , Hrabovska K. 
Published: March 2006

AbstractAn effect of the enamel ageing on the mechanical properties and composition of the steel‐enamel system was monitored by means of conversion electron and transmission Mössbauer spectroscopy, electron‐microprobe analysis, thermogravimetry and microhardness measurement. Two enamels differing in the time delay between their preparation and application on the steel surface (1 day vs 30 days) were used for this comparative study. After the enamelling procedure, the qualitative phase composition of both samples is similar, including α‐Fe, FeO, Fe3O4, α‐Fe2O3, Fe2SiO4 and the FeNi particles. Despite this similar qualitative phase composition of differently aged enamels, the mechanical properties of the samples are significantly different. Copyright © 2006 John Wiley & Sons, Ltd.
Metal clustering during depth profiling of thin films
Authors: Karpuzov D. , He A. , Xu S. 
Published: March 2006

AbstractThin metallic layers of Cu, Cr, or Ag were deposited on Si substrates and then sputtered as in a standard depth profiling mode. The etching was completed by using 1–5 keV Ar+ beam, scanned over the surface. The composition of the exposed etched surface was monitored by X‐ray photoelectron spectroscopy (XPS) or Auger electron spectroscopy (AES). When the metal‐silicon interface was approached, the etching was stopped and the sample surface was analyzed by scanning electron microscopy (SEM) and scanning Auger microscopy (SAM). We observed clusters of metal on the Si substrate. Their characteristic sizes were 30–60 nm for Cu, 60–90 nm for Cr, and 100–200 nm for Ag. The patterns were sensitive to the ion energy—at 1 keV the Cu network was well defined, whereas at 3–5 keV energy the patterns become fuzzy without clear boundaries. The clustering of thin films near the interface can affect the depth profiles in surface analytical techniques, and can be used as a tool to create clusters in nanotechnology. Copyright © 2006 John Wiley & Sons, Ltd.
An electron spectroscopy study of a‐C:H under thermal annealing
Authors: Calliari L. , Filippi M. , Gottardi G. , Laidani N. , Anderle M. 
Published: March 2006

AbstractThe structural changes brought about in hydrogenated amorphous carbon (a‐C:H) by thermal annealing are investigated by photon‐induced electron spectroscopy. The material is found to be stable up to T = 100 °C. From 100 to 400 °C, H effusion is associated with sp3 to sp2 conversion, as revealed by the evolution of the valence states. From 400 to 700 °C, the sp2 sites gather into clusters of increasing size, as revealed by the decreasing binding energy (BE) and increasing asymmetry of the C 1s spectrum. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental determination of the inelastic mean free path (IMFP) of electrons in selected oxide films applying surface excitation correction
Authors: Gurban S. , Gergely G. , Toth J. , Varga D. , Jablonski A. , Menyhard M. 
Published: March 2006

AbstractThe inelastic mean free path (IMFP) of electrons was determined using elastic peak electron spectroscopy (EPES) with Cu, Si, Ag, Ni and Au reference samples.Systematic differences occurred between the experimental and calculated (TPP‐2M) (Tanuma, Powell, Penn) IMFPs, which can be ascribed partly to surface losses. The experimental IMFP was deduced from the integrated elastic peak ratio of the sample and the reference. Experiments were made with the ESA 31 (ATOMKI) and DESA 100 (Staib) electron spectrometers, and covered the E = 0.2–2 keV energy range. The results were evaluated applying Monte Carlo (MC) simulation based on the NIST SRD 64/3.1 database and using the EPESWIN software of Jablonski. The surface excitation correction (surface excitation parameter (SEP)) for SiO2, MgO and Al2O3 was determined using our new procedure applying the model of Chen and Tanuma. This correction reduced the difference between uncorrected, experimentally determined and calculated IMFPs by nearly 50%, which proves the importance of the contribution of surface excitation. The oxide layers studied are insulators. Their surface potential was determined by the energy of the Auger peak. We observed an energy shift of 1–3 eV of the Auger peak positions due to charging. The SEP material parameter resulted in ach = 1.2 for SiO2 and ach = 4 for MgO and Al2O3. Copyright © 2006 John Wiley & Sons, Ltd.
Nitrogen depth profiling in thin oxynitride layers on silicon
Authors: Budrevich A. , Gladkikh A. , Kaganer E. , Sokolovsky M. 
Published: March 2006

AbstractThis paper describes the results of nitrogen depth profiling in nanometer oxynitride layers on silicon, employing dynamic SIMS and time‐of‐flight SIMS. The surface transient effect was studied using surface encapsulation method, and the attractive possibility of time‐of‐flight SIMS profiling with low energy Cs sputtering was demonstrated. Quantification of the nitrogen profiles was performed after a detailed study of the matrix effect in order to correct for the ion yield difference at the oxynitride/silicon interface. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of surface preparation on the evolution of the passive films formed on AISI 304L
Authors: Abreu C. M. , Cristóbal M. J. , Losada R. , Nóvoa X. R. , Pena G. , Pérez M. C. 
Published: March 2006

AbstractIn this work, an insight into the effect of surface roughness in the composition and evolution of the oxide film electrogenerated on an austenitic stainless steel substrate is presented. The obtained results point out the importance of Ni on the oxide layers formed in alkaline media, which can condition their resistance to chloride attack. Polished samples show better corrosion performance than abraded ones owing to Ni enrichment at the metal‐oxide interface. Copyright © 2006 John Wiley & Sons, Ltd.
Characterisation of metal oxide films deposited by non‐hydrolytic ALD
Authors: Evans P. J. , Mutin P. H. , Triani G. , Prince K. E. , Bartlett J. R. 
Published: March 2006

AbstractAtomic layer deposition (ALD) has become an established technique for producing thin films of a wide range of materials. Of particular note is the extensive research on the use of ALD metal oxide films as the replacement for the high‐k SiO2 dielectric layer in future semiconductor devices. In much of this work, metal halides or metallorganics combined with water, peroxide or ozone have served as precursors for the sequential deposition process that forms the basis of ALD. Alternative reaction schemes, such as those in which metal halides are reacted with metal alkoxides, have also been investigated with some success though higher temperatures are often required for film deposition. However, the effect of alternative oxidising species in ALD has not been extensively studied in terms of both their efficacy and their influence on the film growth process. Here we describe recent work on the use of t‐butyl alcohol (tBA) and di‐isopropyl ether (DIPE) for the ALD of titania films from titanium tetrachloride. A quartz crystal microbalance (QCM) was used to monitor film growth in real time. Films were also grown on silicon wafers for post‐deposition analysis. Spectroscopic ellipsometry, atomic force microscopy (AFM), X‐ray diffraction (XRD) and secondary ion mass spectrometry (SIMS) were used for this purpose. The results obtained from this combination of surface analytical techniques will be discussed in detail in order to illustrate the strength of this approach for the elucidation of ALD film growth by means of non‐hydrolytic reactions. Copyright © 2006 John Wiley & Sons, Ltd.
XRD, AFM and IR investigations of ordered AlGaAs2 phase in epitaxial AlxGa1–xAs/GaAs (100) heterostructures
Authors: Domashevskaya E. P. , Seredin P. V. , Lukin A. N. , Bityutskaya L. A. , Grechkina M. V. , Arsentyev I. N. , Vinokurov D. A. , Tarasov I. S. 
Published: March 2006

AbstractThe lattice constant of AlxGa1−xAs epitaxial alloys with various Al‐As(x) content is determined for AlxGa1−xAs/GaAs (100) heterostructures grown by MOVPE epitaxy using X‐ray diffractometry and X‐ray back‐reflections method. An ordered AlGaAs2 (superstructural) phase was found in epitaxial heterostructures for x ∼ 0.50. The lattice constant of this phase along c axis is smaller than the double lattice constants of an Al0.50Ga0.50As alloy. Infrared (IR) reflection spectra of lattice vibrations were investigated in epitaxial heterostructures of AlxGa1−xAs/GaAs (100) with different concentrations of Al in cation sublattice. In the sample with x ∼ 0.50, besides two main vibration modes some additional ones were found that correspond to superstructure ordered phase AlGaAs2. Atomic‐force microscopy (AFM) of the sample surface with x ∼ 0.50 demonstrated the presence of areas with ordered nano‐relief having period of ∼115 nm that can be related with superstructure phase of AlGaAs2. Copyright © 2006 John Wiley & Sons, Ltd.
TEM and XANES investigations and optical properties of SnO nanolayers
Authors: Domashevskaya E. P. , Chuvenkova O. A. , Kashkarov V. M. , Kushev S. B. , Ryabtsev S. V. , Turishchev S. Yu. , Yurakov Yu. A. 
Published: March 2006

AbstractTEM, XANES and optical investigations show that tin film oxidation starts with the formation of tetragonal tin monoxide, which is converted to unstable orthorhombic tin dioxide with the increase of annealing temperature, transferring, in its turn, into stable tetragonal tin dioxide. In our experimental conditions, no complete transition of the orthorhombic dioxide phase into the tetragonal one is observed up to a temperature of 750 °C.According to XANES, data oxidation in the air of tin film surfaces starts at room temperature with the formation of an amorphous Sn‐O layer. Probably, this surface layer corresponds to an amorphous membrane, which is formed at the initial stage of interaction at the phase boundaries. After 1 h annealing at temperature intervals of 170–240 °C this surface layer (∼ 5 nm) mainly consists of monoxide phase. Annealing at 450–750 °C leads to only tin dioxide formation in the surface layer.At least two edges can be observed at the fundamental absorption region of oxide film obtained under annealing at a temperature below 600 °C, which corresponds to two values of band gaps: Eg1 = 2.5–2.7 eV and Eg2 ∼ 3.4 eV. With an increase of the annealing temperature up to 600 °C, only one absorption edge can be observed with a greater band gap of Eg2 ∼ 3.4 eV. This absorption edge corresponds to that of tin dioxide with a composition of SnO2 for both modifications observed in our experiments. The second edge with the narrower band gap corresponds to tin monoxide, SnO, and is observed at a temperature below 550 °C. Copyright © 2006 John Wiley & Sons, Ltd.
Fabrication and characteristics of TiO2 films by a microwave drying technique
Authors: Jaroenworaluck Angkhana , Panyathanmaporn Thammarat , Soontornworajit Boonchoy , Supothina Sitthisuntorn 
Published: March 2006

AbstractPreparation of TiO2 film coatings on various substrates for photocatalysis applications has been studied. A non‐aqueous sol was prepared using tetra‐propylorthotitanate (Ti(OPr)4) and 1,2 butadiol (Bu(OH)2) as starting chemicals, for casting onto a glass substrate. From this synthesis method, nanosized TiO2 consisting of pure anatase phase could be prepared, and was characterized using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). To apply the synthesis process for fabrication of TiO2 film coatings, commercial nanosized TiO2 powder, Degussa P‐25, was added and intimately mixed into the as‐prepared sol as a source of TiO2 nanoparticles. The surface of the glass substrate used in this study was cleaned, polished, and chemically etched before coating. To control film thickness, multi‐casting of the sol onto the substrate before the gelatinization process was applied. Prior to calcination, the gel film was dried by means of a domestic microwave oven, heating at 800 W for 2 min. The resulting TiO2 films were then characterized by optical microscopy (OM), field emission scanning electron microscopy (FE‐SEM), and UV/VIS/NIR spectrometry, to identify the film characteristics. The phases present in the films were identified by XRD. From this coating technique, continuous TiO2 films could be prepared. No cracks were observed on these films. Copyright © 2006 John Wiley & Sons, Ltd.
Surface and interface analysis of complex polymeric paint formulations
Authors: Hinder Steven J. , Watts John F. , Lowe Chris 
Published: March 2006

AbstractComplex model formulations of coil coatings have been investigated by X‐ray photoelectron spectroscopy (XPS), angle resolved X‐ray photoelectron spectroscopy (ARXPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). High‐resolution monochromated XPS C 1s spectra have been peak fitted and can account for all the carbon functionalities of the components included in these complex paint formulations.The addition of small quantities of additives such as flow agents is shown to induce significant changes in the surface composition of these coatings, and ARXPS reveals the additive outer layer to be 1–2 nm thick. Furthermore, in our investigation of a poly(vinylidene difluoride) (PVdF)‐based topcoat, analysis of the high binding energy background of the XPS F 1s peak indicates that the PVdF component of the topcoat formulation is to be found below a surface segregated flow agent layer. Use of a silicone‐based flow agent in a polyurethane (PU)‐based primer formulation is shown to result in the migration of the flow agent into and through the PVdF topcoat. The silicone‐based flow agent is ultimately observed at the PVdF topcoat's air‐coating surface.XPS analysis of a PVdF topcoat–PU primer interface buried 20 µm below the topcoat's air‐coating surface, exposed by ultra‐low‐angle microtomy (ULAM), suggests diffusion of fluorine‐bearing materials from the topcoat into the top few nanometres of the underlying PU primer. Imaging ToF‐SIMS analysis of a PVdF–PU interface exposed by ULAM reveals that a substantial fraction of an acrylic co‐polymer included in the topcoat formulation segregates to the topcoat–primer interface where it enhances the adhesive properties exhibited by the PVdF topcoat towards the PU primer. Copyright © 2006 John Wiley & Sons, Ltd.
Coating of Ti–6Al–4V alloy with pure titanium film by sputter‐deposition for improving biocompatibility
Authors: Sonoda T. , Saito T. , Watazu A. , Katou K. , Asahina T. 
Published: March 2006

AbstractCoating of Ti–6Al–4V alloy substrates with pure titanium film by magnetron d.c sputtering in Ar gas was examined in order to improve the biocompatibility of the alloy, because a pure titanium barrier layer prevents harmful substances such as aluminum or vanadium from leaching into biological tissues. The effects of the pure titanium barrier layer on the cytocompatibility of the titanium alloy were investigated. Under visual observation, the pure titanium film appeared to be uniform and adhesive. Under SEM, the surface of the deposited pure titanium film was observed to consist of fine accumulating and aggregating particles. According to the Auger electron spectroscopy (AES) depth‐profiles of Ti and Al for the deposited titanium film and Ti–6Al–4V alloy substrate, it was confirmed that no aluminum atoms diffused to the film surface from the alloy substrate. Thus, it was expected that the obtained titanium film could improve the biocompatibility of the alloy as a barrier layer, which prevents aluminum atoms from leaching into biological tissues. On the basis of the results of the in vitro cytotoxicity test, it was found that the viability, i.e. the ratio of living cells to the sum of living cells and dead cells, was higher for the titanium film than for the alloy. Therefore, the deposited titanium film exhibited better cytocompatibility than the Ti–6Al–4V alloy, leading to the conclusion that the cytocompatibility of the alloy was improved by coating it with the titanium film. Copyright © 2006 John Wiley & Sons, Ltd.