bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple method of depth profiling (stratifying) contamination layers, illustrated by studies on stainless steel
Authors: Seah M. P. , Qiu J. H. , Cumpson P. J. , Castle J. E. 
Published: May 2005

AbstractStainless‐steel artefacts are used as reference masses for the calibration of balances and instruments involving force. The surfaces of these masses react with the environment, leading to changes in the chemistry of the steel surface, accretion of surface contamination layers and a dynamic absorption of moisture in those contamination layers. In order to understand these layers, to stabilize or correct for the concomitant mass changes, it is important to define what chemical states are developing and their stratification at the surface. Four chemical states are identified in the oxygen XPS peak and four in the carbon peak. In the project a very large number of samples are studied and so a rapid, simple stratifying method has been developed requiring measurements at only two angles of emission. The method, which involves a simple ratio of the peak intensities either after separation of the states or by using the peak envelope, or just by ratioing the whole spectra at the two angles enables the stratification and other parameters to be readily determined for all eight peaks.
18O tracer study of the oxidation of zircaloy‐4 in steam
Authors: Matsuda Y. , Anada H. , Bishop H. E. 
Published: May 2005

AbstractThe corrosion resistance of Zircaloy‐4, used as fuel cladding in pressurized water reactors, in steam at 400°C is related to the annealing temperature used in fabrication. This change in corrosion behaviour appears to be related to the size and composition of intermetallic compound precipitates, which vary with annealing temperature.A SIMS study has been undertaken to clarify the mechanisms responsible for these variations in the initial stages of corrosion of Zircaloy‐4. A set of samples subjected to different annealing temperatures have been oxidized, initially in normal steam and subsequently in steam enriched in H218O. Corrosion mechanisms have been followed using depth profiling in a Cameca IMS 3F microscope together with three‐dimensional depth profiles and imaging of taper sections using a gallium microprobe (VG Scientific).Iron and chromium, present in intermetallics in the alloy, remain localized within the oxide scale. The size and frequency of these local concentrations of iron and chromium reflect the distribution of these elements in the alloy. There is, however, some diffusion of these elements into the surrounding oxide, the iron diffusion being greater than that for chromium. The18O tracer studies indicate that grain boundary transport of oxygen dominates the initial oxide growth process for Zircaloy‐4.
Application of tougaard background subtraction to XPS spectra of passivated Fe–17 Cr
Authors: Norgren B. S. , Somers M. A. J. , De Wit J. H. W. 
Published: May 2005

AbstractIn order to examine the spectra of films formed during the polarization of an Fe–17 Cr alloy in 0.5 M sulphuric acid, it is necessary to separate the overlapping spectral components of the film and substrate. The procedure for peak separation and background subtraction as proposed by Hansen and Tougaard was followed and is described in detail for the present case. On applying the procedure it was observed that the results obtained are sensitive to the value used for the film thickness in calculating the contribution from the substrate to the overall spectrum. Thus, the film thickness can be regarded as an outcome of the procedure. The elastic XPS spectrum of the film remaining after peak separation and background subtraction was compared to that obtained after subtraction of a Shirley background followed by curve fitting of the substrate contribution.
Observation of the action of penicillin on bacillus subtilis using atomic force microscopy: Technique for the preparation of bacteria
Authors: Kasas S. , Fellay B. , Cargnello R. 
Published: May 2005

AbstractAtomic force microscopy (AFM) is a very convenient means of studying hard and flat samples with atomic resolution. Biological objects, usually soft and rough, are sometimes difficult to image using this technique. Bacteria, which are too small to be observed with good resolution using the optical microscope, are hard enough to be observed with an atomic force microscope at a level of magnification similar to that obtained with the electron microscope. These microorganisms can be prepared for AFM imaging using very rapid and simple techniques. We discuss here different preparation methods and substrates that can be used for the preparation of bacterial samples for observation with AFM. We also show images of different species of bacteria, such as Escherichia coli, and Bacillus subtilis, taken with the atomic force microscope in constant force and constant height modes, as well as images demonstrating the action of penicillin on B. subtilis.
Use of parallel imaging XPS to perform rapid analysis of polymer surfaces with spatial resolution >5 μm
Authors: Forsyth N. M. , Coxon P. 
Published: May 2005

AbstractX‐ray photoelectron spectroscopy (XPS or ESCA) is one of the most common surface analytical techniques available. It has proved over many years to be invaluable in the analysis of elemental and chemical species on surfaces. The recent developments of this technique towards spatially resolved XPS information has made it possible to use XPS for analysis of very small features on insulating materials such as polymer surfaces, on which other high spatial resolution techniques such as Auger electron spectroscopy (AES) suffer difficulties generated by, for example severe sample charging effects.The new VG ESCALAB 220iXL from VG Scientific (Fisons Instruments) uses parallel imaging together with a magnetic objective lens to provide chemical images of better than 5 μm spatial resolution in just a few minutes. Subsequent point analysis using selected small‐area XPS can be performed on any feature in the images down to 7 μm resolution. In combination with this unique parallel imaging facility, a new high‐intensity x‐ray monochromator source makes fast chemical state imaging at high spatial resolution relatively routine. Several examples of the analysis of polymer surfaces wil be shown, including chemical state imaging of the C 1s, CC, and CO bonding states from 15 μm features.
Activities of ISO technical committee 201 on surface chemical analysis
Authors: Powell C. J. , Shimizu R. 
Published: May 2005

AbstractA status report is given on activities of ISO Technical Committee 201 (ISO/TC 201) on Surface Chemical Analysis. The committee has seven subcommittees which met for the first time in 1993. Information is given on the working groups that have been established for specific purposes. We show national participation in ISO/TC 201 and its subcommittees, and we identify the chairmen and secretariats of the subcommittees and the conveners of the working groups.
Ion sputter rates and yields for iron‐, chromium‐ and aluminium oxide layers
Authors: Viefhaus H. , Hennesen K. , Lucas M. , Müller‐Lorenz E. M. , Grabke H. J. 
Published: May 2005

AbstractLayers of the oxides FeO, Fe3O4, Fe2O3, Cr2O3 and Al2O3 were prepared by evaporation of the corresponding metal layers onto a preoxidized Si substrate and oxidation at elevated temperature. The oxidation was conducted under thermodynamically well‐defined conditions so that the pure oxide phases noted were obtained. The oxide layer thickness was calculated from the thickness of the initial metal film, which was determined by chemical analysis and from the frequency change of a quartz crystal upon evaporaton. Auger electron spectroscopy depth profiles of the oxide layers were measured during Ar+ sputtering, and the sputter time necessary to reach the interface oxide/substrate was determined. The determination of this sputter time was not very exact, because the transition from oxide to substrate in the profile was rather gradual, owing to the roughness and crystalline character of the oxide layers that causes inhomogeneous sputtering. However, from the sputter time, oxide thickness and ion beam current, the sputter rates were obtained for the oxides noted (in nm μA−1 cm−2 min−1) and were compared to the sputter rate of amorphous Ta2O5, which is generally used as the sputter reference standard. Considerable differences were found. The results will lead to more reliable determinations of oxide scale thicknesses by sputtering.
Small‐area XPS investigation on ion‐induced chemical modifications during depth‐profiling of an AlxGa1−xas/gaas structure
Authors: Padeletti G. , Ingo G. M. 
Published: May 2005

AbstractDepth profiling by argon ion sputtering was carried out on an Al0.3Ga0.7As/GaAs layered structure, using different ion‐beam energies (up to 5 keV) and keeping constant the ion current density. When the steady state condition was reached in the ternary layer, in order to investigate the ion‐induced chemical modifications, angle resolved small‐area x‐ray photoelectron spectroscopy (SA‐XPS) investigations were carried out on the bottom of the crater resulting from the ion‐beam erosion. In order to study the different regions of the damaged layer, attention was focused on the As 3d, Ga 3d and Al 2p signals as well as on the As 2p3/2 and Ga 2p3/2 peaks, which are spread over an energy range about 1000 eV wide and therefore photoemitted from different depths. The results show the different ion‐induced effects on the chemical composition of the Al0.3Ga0.7As layer, such as arsenic preferential sputtering, aluminium Gibbsian segregation and further, the formation of elemental species, as a function of the Ar+ energy.
A spectroscopic analysis of plasma polymers prepared from a series of vinyl sulphones
Authors: Ward Alison J. , Short Robert D. 
Published: May 2005

AbstractPlasma polymers (PPs) have been prepared from methyl vinyl sulphone (MVS), ethyl vinyl sulphone (EVS) and vinyl sulphone (VS). The ratio of radio frequency (r.f.) power (W) to flow rate of monomer (F) or W/F is an important parameter in plasma polymerization. PPs prepared at low and high W/F were analysed by x‐ray photoelectron spectroscopy (XPS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and grazing angle infra‐red (GAIR) spectroscopy.XPS revealed that significant quantities of the sulphone group had been retained from the monomer. The greatest retention was observed in the PPs that had been prepared at low W/F, where the majority of the sulphur was present as RSO2R/H. The remaining sulphur being in RSOR/H and RSR/H environments. This trend was reversed in the PPs prepared at high W/F.The negative secondary ion mass (SIM) spectra of PPs prepared at high and low W/F were examined and structures proposed for the prominent ions. The relative intensities of these ions were different for the PPs prepared at high and low W/F. This showed that there had been a greater retention of structures from the monomer in the PPs that were prepared at low W/F.The GAIR spectroscopy confirms the presence of sulphone groups throughout the PP film. It also shows that carbonyl groups are present which cannot be confirmed by XPS alone.
X‐ray photoelectron spectroscopy and scanning electron microscopy of β‐FeSi2 films grown by Ion Beam assisted deposition
Authors: Armelao L. , Terrasi A. , Boaro M. , Ravesi S. , Granozzi G. 
Published: May 2005

AbstractThis paper reports the investigation of polycrystalline β‐FeSi2 films grown by Ion Beam Assisted Deposition (IBAD), performed by using a broad Ar+ beam bombarding (001) Si substrates during the evaporation of Fe atoms. Several energies (200–650 eV) and current densities (10–70 μA cm−2) have been used for the Ar+ beam, keeping the Fe evaporation rate at about 0.08 nms−1. The formation of the silicide was achieved by in situ thermal annealing at T = 600 °C, performed during or after the deposition process. Rutherford Backscattering Spectroscopy (RBS), Scanning Electron Microscopy (SEM) and X‐Ray Photoelectron Spectroscopy (XPS) have been used to study the stoichiometry, the morphology and the chemical status of several samples obtained using different ion beam parameters. Strong morphological improvements, such as smoothing and pinhole closing, are observed for the IBAD films grown during thermal annealing. The XPS depth profiling technique has been used to investigate the morphology of the silicide/Si interface.
Ion bombardment induced modification of polyvinyltrimethylsilane studied by XPS
Authors: Tóth A. , Bertóti I. , Khotimsky V. S. 
Published: May 2005

AbstractPolyvinyltrimethylsilane films were bombarded by 1 keV and 5 keV Ar+ and N2+ ions up to fluences of about 1017 ions cm−2. XPS studies showed the actual surface composition and the chemical bonding to be dependent on the nature of the projectile applied, the ion energy, the fluence, the presence or absence of low energy flooding electrons, and the time elapsed between the ion beam treatment steps. Exposure of the ion beam treated samples to ambient air resulted in a strong uptake of oxygen, the attack of which took place predominantly on Si and to a lesser extent on C.
Bulk‐to‐surface diffusion measurements in a (111)Cu(0.1 at.%)Sn single crystal using a linear programmed heating method
Authors: Viljoen E. C. , du Plessis J. 
Published: May 2005

AbstractUsing the recently proposed method of linear heating, the diffusion parameters (D0 and E) were determined for a Cu(0.1 at.%)Sn single crystal. In this method, the sample temperature is increased linearly with time and the surface concentration is measured by Auger electron spectroscopy as a function of temperature (or time). The main advantage of this method is that the diffusion parameters may be obtained from a single run. Four runs were made at 0.1, 0.25, 0.5 and 1.0 °C s−1 and the average diffusion parameters (D0 = 9.2 × 10−4m2 s−1 and E = 189 kJ mol−1) agree well with other published values.
Quantitative depth profile analysis by EPMA combined with Monte‐Carlo simulation
Authors: Ammann Norbert , Karduck Peter 
Published: May 2005

AbstractCalibrated x‐ray intensities of arsenic and gallium, implanted with various ion‐energies and doses into silicon, were measured over a wide range of electron‐beam energies and angles of incidence. For the first time Monte‐Carlo (MC) simulation was applied to evaluate the EPMA‐data with respect to depth‐profiles parameters, particularly at non‐normal electron incidence. Accurate agreement between MC‐simulated and measured k‐ratios was obtained in the whole range of excitation conditions applied. The resulting range parameters determined from the EPMA data agree closely with those obtained by other authors from RBS or NAA but like these they show systematic deviations from theoretical predictions. Actual measurements on samples implanted with 1014 ions cm−2 clearly prove the limits of detectability for As and Ga in Si to be below this number. Similar sensitivity was found for elements with atomic numbers Z > 10 but for light elements (Z ⩽ 10) the limit of detectability is increased by about one order of magnitude. Provided the concentrations are appropriate, EPMA combined with MC‐simulation is a promising technique for the accurate quantitative, non‐destructive, and spacially resolved analysis of depth‐profiles.
Factor analysis, a useful tool for solving analytical problems in AES and XPS: A study of the performances and limitations of the indicator function
Authors: Arranz A. , Palacio C. 
Published: May 2005

AbstractComputer simulations have been used in order to investigate an objective procedure to determine the number of principal factors when factor analysis is used for solving analytical problems in AES and XPS. The indicator (IND) function has been used in the investigation. The simulated results show that the IND function could be used for detecting and solving sampling misalignment problems. Furthermore, the S/N ratio, the severe overlap of spectra and the relative importance of the various factors involved can limit the sensitivity of the IND function to determine the correct number of principal factors.
Ambient oxygen effect in Ga+ FIB‐SIMS
Authors: Sakamoto Tetsuo , Tomiyasu Bunbunoshin , Owari Masanori , Nihei Yoshimasa 
Published: May 2005

AbstractEnhancement of Al positive secondary ion emission by ambient oxygen was investigated by Ga+ focused ion beam (FIB) SIMS instrument at various combinations of oxygen partial pressure and scanning area of FIB. A model calculation was made which assumes that the amount of enhancement of single‐charged positive secondary ion emission is directly proportional to the oxygen concentration in the mixing layer. The observed amount of enhancement showed a characteristic dependence both on the oxygen dose and the beam scanning area. The model calculation well reproduced most of the features quantitatively.
Charging and mixing effects during the XPS analysis of mixtures of oxides
Authors: Fernández A. , Espinós J. P. , Leinen D. , González‐Elipe A. R. , Sanz J. M. 
Published: May 2005

AbstractIn this article we present an XPS analysis of mixtures of Al2O3 and TiO2 powders of different relative size in order to study differential charging effects. To illustrate some of the possible situations we have studied the behaviour of three different samples: (1) very large (microns) and porous particles of Al2O3 supporting TiO2 particles of relatively small size (300 Å); (2) Al2O3 and TiO2 particles of similar size (300 Å); and (3) very small particles (20–30 Å) of TiO2 dispersed in Al2O3 particles of 300 Å. The observed effects are then analysed by using Auger parameters and relative binding energies and discussed in terms of the different morphologies of the samples, as determined by TEM. The influence on charging of an electron flood gun and of Ar+ sputtering is also presented. In addition, ion‐induced mixing effects have been clearly observed in the case of very small particles of TiO2 dispersed on alumina.
Database of relativistic elastic scattering cross‐sections for calculations of photoelectron and Auger electron transport
Authors: Jablonski A. , Tougaard S. 
Published: May 2005

AbstractQuantitative applications of electron spectroscopies, AES and XPS, should be based on theoretical models describing realistically the electron transport in solids. Detailed knowledge of elastic scattering cross‐sections due to the elements constituting a given solid is necessary in such calculations. To some extent, such data are available in the literature, but a complete data set in the form of a computer controlled database is not available. An extensive software packet is described in the present article for providing relativistic elastic scattering cross‐sections for elements with atomic numbers up to 96. The energy range for each element varies from 50 to 10000 eV in steps of 1 eV. The software packet has the following options: (1) visualization of the differential elastic scattering cross‐sections in different coordinate systems; (2) creation of files containing the elastic scattering cross‐sections for specified elements, energies, and coordinates; (3) creation of random number generators providing the polar scattering angles to be used in Monte‐Carlo simulation of the transport of electrons in solids; and (4) testing the performance of the created random number generators.
Deposition of CeO2 on Si(111) studied by LEED, AES, XPS and RBS
Authors: Guillaume C. E. , Vermeersch M. , Sporken R. , Verbist J. J. , Mathot S. , Demortier G. 
Published: May 2005

AbstractThe deposition of CeO2 on Si(111) has been studied by low energy electron diffraction (LEED), Auger electron spectroscopy (AES), x‐ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). LEED shows the CeO2 layer to grow in the (111) orientation. The formation of a silicon oxide layer at the interface is observed. The thickness of this oxide layer is found to vary between about 1 and 8 nm, depending on the thickness of the CeO2 layer. A model for the growth of CeO2 and for the formation of the silicon oxide layer at the interface is proposed.
High‐resolution electron‐energy‐loss spectroscopy of hydroxyl groups at the surface of bulk insulating oxides
Authors: Coustet Valérie , Jupille Jacques 
Published: May 2005

AbstractThe capability of high‐resolution electron‐energy‐loss spectroscopy to study adsorbates at the surface of bulk insulating oxides has been applied to the cases of OH/MgO(100) and OH/α‐Al2O3(0001). On MgO(100), two types of OH have been identified, either bonded to surface Mg ions (A type) or due to proton adsorption on surface oxygen ions (B type). Dense OH adlayers on MgO(100) (5‐coordinate Mg) have been seen to correspond to νOH(A) = 3690 cm−1 (νOH > 3700 cm−1 being suggested to be related to defects and/or low coverages). On α‐Al2O3(0001), a sharp stretching band νOH has been recorded at 3720 cm−1 and assigned to OH bonded (or bridge‐bonded) to Al in octahedral position.
Surface reactions at the controlled structure of SrTiO3(001)
Authors: Kudo Masahiro , Hikita Tokihisa , Hanada Takashi , Sekine Rika , Kawai Maki 
Published: May 2005

AbstractThe surface structures and reactions on the single domained surfaces of SrTiO3(001) are investigated using MBE and various surface characterization techniques, such as RHEED, UPS and XPS. The selective formation of the two types of SrTiO3(001) surfaces, the TiO2 terminated and the SrO terminated surfaces, was carried out by Bi deposition/desorption cleaning method and Sr deposition, followed by oxidation in the NO2 atmosphere. It is shown that both surfaces have increased atomic distance between the first and the second layers, and the outward displacement of the first layer oxygen atoms. Surface reaction of H2O was investigated in relation to the Ti3+ defects formed by Ar+ bombardment, with the aim of obtaining knowledge on the reaction between surface functional groups and organometallic compounds at the well‐ordered surfaces.
Magic angle for surface roughness for intensity ratios in AES/XPS
Authors: Werner Wolfgang S. M. 
Published: May 2005

AbstractThe influence of surface roughness on total as well as angle‐dependent signal electron intensities has been studied by means of an effective and simple theoretical model. It was found that the influence of surface roughness may be accounted for in the usual formalism for AES/XPS by using an effective depth distribution function (DDF). Comparison of the model with experimental results and Monte Carlo calculations are very satisfactory and indicate that the model developed here should provide useful guidance for quantifying the influence of surface roughness in XPS/AES. For an emission angle of ∼ 35°, the depth distribution function assumes an exponential form with an effective attenuation length varying only by a few per cent as the relative surface area, which characterizes the roughness, is varied over a large range. This result implies that the influence of surface roughness on a given intensity ratio is very small for this geometry and may usually be neglected. This statement not only pertains to a layered sample but applies to a specimen with an arbitrary depth profile. Generally, the effective DDF is dominated by the influence of surface roughness, while the effects of elastic scattering are less pronounced. In this case, the combined influence of surface roughness and elastic scattering is simpler to describe than the influence of elastic scattering on the signal electron emission process from an ideally flat sample.