bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitridation of polycrystalline titanium as studied by in situ angle‐resolved x‐ray photoelectron spectroscopy
Authors: Ermolieff A. , Bernard P. , Marthon S. , Wittmer P. 
Published: May 2005

AbstractNitridation of polycrystalline titanium was investigated in situ at about 550°C by angle‐resolved x‐ray photoelectron spectroscopy (XPS). The nitrogen pressure was varied from 10−4mbar to 1 mbar. The distribution of nitrogen in the titanium and the chemical bonding present were deduced from XPS measurements. Titanium nitridation passes through several stages as a function of the nitrogen exposure. The nitrogen concentration varies linearly with the logarithm of pressure and dose. Using the modified Ritchie‐Hund theory it was shown that the kinetics of titanium nitridation follows a cubic law.
Auger line relative intensities as a tool for the characterization of oxides formed during the oxidation of single crystals of dilute CuMn alloys
Authors: Van Steene G. , Jardinier‐Offergeld M. , Bouillon F. 
Published: May 2005

AbstractA chemical effect affecting the shape of the copper, manganese and oxygen Auger lines provides a very useful tool for characterization of the oxides formed during high temperature and low pressure oxidation of dilute CuMn alloys.The state of oxidation of these elements changes the electron distribution in the valence bands, and the relative amplitudes of the Auger transitions involving one or two valence levels have been used as a measure of this effect.
Oxidation of NiCr and NiCrFe alloys at room temperature
Authors: Steffen J. , Hofmann S. 
Published: May 2005

AbstractThe primary stages of the oxidation of NiCr23 and of NiCr21Fe12 and the final oxide layers were studied at room temperature and oxygen pressures between 10−6 Pa and 10−4 Pa using AES and XPS. The composition of the surface during oxygen exposure was monitored by continuous recording of the Auger transitions M23 VV and L3M23V of the metallic components and the KL23L23 transition of oxygen. The low energy M23VV transitions are especially indicative of the present chemical state which is additionally characterized by the 2p photoelectron spectra. After different oxygen exposures, the thickness of the oxide layers was determined by angle resolved AES, XPS results, and by sputter depth profiling which also gives the elemental in depth distribution. It is concluded that the initial preferential oxidation of Cr is followed by a surface enrichment and oxidation of the remaining elements with lower affinity to oxygen, i.e. Ni in NiCr and both Ni and Fe in NiCrFe.
Automated interface recognition in auger sputter depth profiling
Authors: Hill Malcolm D. 
Published: May 2005

AbstractA range of materials systems has been studied in order to establish whether remote sensing of proximity to an abrupt hetero‐interface can be achieved, in real‐time, during Auger depth profiling. Changes in the absorbed electron current, during both electron and ion beam irradiation of the sample, and variations in the secondary ion yield during sputtering have been measured. In each materials system one or more of these signals has been found to indicate an approaching interface at a significant distance from the onset of the interface in the Auger profile. The application of these findings to the development of methods of acquiring Auger depth profiles rapidly, but without loss of depth resolution at interfaces, is discussed.
Interface analysis using elastic scattering in the transmission electron microscope: Application to the oxidation of silicon
Authors: Ross F. M. , Stobbs W. M. 
Published: May 2005

AbstractWe describe the method of Fresnel fringe contrast analysis and discuss the results obtained by applying the technique to the analysis of the oxides first formed on silicon during wet oxidation. The accuracy of the method is limited at present by the effects which inelastic scattering has on the microscope images. Although these effects are hard to quantify, we show that accurate results can be obtained concerning the sharpness or diffuseness of the Si/SiO2 interface at the atomic level. Combining the results obtained by this method with those found by using high‐resolution electron microscopy for oxides of different thicknesses we are able to conclude that there is a SiOx layer of probably 0.25 nm present during the first stages of oxide growth, but that a further 0.5 nm of crystalline oxide develops well after the start of the oxidation, when the oxide layer is between 2 and 4 nm thick. The implication of these results in relation to the various mechanisms for silicon oxidation which have been proposed are discussed briefly.
Experimental detection limits in scanning auger microscopy at high lateral resolution
Authors: Chazelas J. , Cazaux J. , Gillmann G. , Lynch J. , Szymanski R. 
Published: May 2005

AbstractUsing a scanning Auger microscope at 100 keV primary beam energy it has been possible to analyse a dispersed catalyst particle by particle. The elemental analysis of a 8 nm particle has been obtained for which the number of Pd atoms being detected is estimated to be less than 4000, leading to a detectable mass of 7 × 10−19 g. A silicon sub‐monolayer buried in a GaAs matrix has also been detected, operating at oblique incidence with a 20 nm beam size (minimum detectable concentration < 2 × 10−3). These preliminary experiments illustrate the potential of performing Auger spectroscopy at unconventional primary beam energies (with a field emission gun) when high lateral resolution is required.
Thickness determination of oxide layers on spherically‐shaped metal powders by ESCA
Authors: Nyborg L. , Nylund A. , Olefjord I. 
Published: May 2005

AbstractThe effect of the spherical shape of powder on the determination of oxide thickness in ESCA analysis in investigated. A theoretical model, which takes account of the angular dependence of the X‐ray flux, the photoelectron intensity and the etch rate, is outlined. The model agrees well with experimental depth profiles obtained for Al and Fe powders covered with thin oxide layers (14–20 Å). By using an effective escape depth factor, the thickness of thin oxide layers can be estimated from the oxide and metal intensities. The thickness of oxide layers greater than three times the electron mean free path can be estimated from the etch depth where the metal itensity is 65% of its maximum.
Tinplates and tin/chromium interfaces studied by electron spectroscopies
Authors: Lauristsen F. R. , Onsgaard J. , Vinternes H. 
Published: May 2005

AbstractTinplates used for can manufacturing have been analysed by XPS in combination with noble gas ion bombardment. In order to study the influence of the tin coating on the passivation layer, tinplates with different coatings were analysed. In contrast to the chemical measurements a difference was found between a tin coating equal to 1.0 g Sn/m2 and plates with larger coatings. The difference was diminished after a period of six months. With the purpose of clarifying the role of diffusion effects separate investigations of the Sn/Cr interface were conducted. The time effects are explaned by a model where diffusion of chromium due to the presence of tin and due to oxidation of metallic chromium is considered.
Supported rhodium catalysts. Support effects on state and dispersion of the rhodium
Authors: Zaki M. I. , Tesche B. , Kraus L. , Knözinger H. 
Published: May 2005

AbstractUsing SiO2, γ‐Al2O3 as typical examples for acidic, amphoteric and basic oxides, the effect of the support nature on the behaviour of Rh was studied by temperature‐programmed reduction, transmission electron microscopy and IR spectroscopy of adsorbed CO. Reduction is much easier on SiO2 than on Al2O3 and MgO. The highest metal dispersion is stabilized on Al2O3, while particle aggregation to particles with diameters of up to 6 nm occurs on SiO2, during severe reduction and on MgO even under mild reduction conditions. The mobility of RHo atoms and the nucleation rates seem to be larger on MgO than on the other supports. In the presence of CO, the very small particles are disrupted with formation of Rh+(CO)2 complexes at temperature below 300 K; at higher temperatures CO acts as a reducing agent and induces particle growth. It seems that particle disruption is favoured on the supports having the more acidic OH groups. Apart from the support nature, the nature of the precursor complex in solution and the solvent play a decisive role for the reducibility of rhodium.
XPS and SIMS characterization of metal oxide/amorphous silicon—carbon interfaces
Authors: Eicke A. , Bilger G. 
Published: May 2005

AbstractFor different a‐SiC:H/metal oxide (TCO) layers—used for thin film solar cells—migration of metal atoms into the amorphous film, SiOx formation at the interface and reduction of TCO were investigated by SIMS and XPS depth profiling. Zinc oxide seems to be most suitable as a TCO and blocking layer, as the SiOx formation which limits transport of charge carriers is rather low compared to that from SnO2 contacts, and as no Zn is detected in a‐SiC:H in contrast to SnO2 and indium tin oxide ITO with 0.3% Sn and 20 ppm In, the latter acting as counterdopand in p+ a‐SiC:H layers. From correlations between SI yields and elemental concentrations determined by XPS, the quantification of different elements, as well as silicon oxide and metal migration can be deduced from SI intensities. In particular Si+ enhancement is a sensitive indicator for SiOx formation. By these correlations SIMS depth profiling enables fast, quantitative and highly sensitive investigations of numerous samples for optimization of preparation conditions. This is demonstrated in detail for a‐SiC:H/ZnO.
Quantitative Auger analysis of passive films formed on stainless steels
Authors: Lorang G. , Basile F. , Da Cunha Belo M. , Langeron J.‐P. 
Published: May 2005

AbstractDepth profiling analysis of passive films grown on the surface of Fe17Cr, Fe13.5Cr3.5Si and Fe12Cr5Al alloys (with or without Mo additions) in acidic and basic media has been performed by Auger electron spectroscopy (AES) and ion sputtering. Original depth concentration profiles for oxidized iron and chromium inside the passive film and unoxidized (metallic) components of the alloys were extracted using the sequential‐layer‐sputtering model with the assumption of a step‐like interface between the passivated overlayers and the metallic substrate. A quantitative analysis requires an accurate adjustment of the sputter rate employed as a fitting parameter (related here with numerical values of inelastic mean free paths). In this way, some consistent relationships can be established between the absolute atomic depth distributions of elements constituting the passive films, its thickness and the electrochemical characterization of the alloy resistance with regard to pitting corrosion.
Adhesion of polymers to metals: A review of the results obtained studying a model system
Authors: Boiziau C. , Lecayon G. 
Published: May 2005

AbstractFollowing a rapid overview of the various mechanisms involved in the process of polymer adhesion to metals, modelling is attempted in order to describe, at molecular scale, the metal—polymer interface in its technological reality. In particular, the concept of an active site is explained and the role of these sites in bonding mechanisms is illustrated.The model is then verified in laboratory using experimental and theoretical techniques appropriate for the problem posed. Electrochemistry in organic environment is used to impart to the surfaces a homogeneous acid or basic character (i.e. electron acceptor or donor) and to set up an intense anisotropic electrical field allowing nonrandom simulation of the fields induced by the roughness of the potential of the surface of an industrial object. It is thus demonstrated that the establishment of a strong metal—polymer bond results from so‐called Lewis acid—base reactions activated by the interfacial electrical field.Finally, the ageing study of the metal—polymer system thus obtained shows that the interface is stable relative to atmospheric oxygen and that vacuum pyrolysis converts the polymer into a carbon fibre strongly bonded to the metal.
Study of the Al/PET interface in relation with adhesion
Authors: De Puydt Y. , Bertrand P. , Lutgen P. 
Published: May 2005

AbstractThermally evaporated aluminium thin layers have been deposited on two different industrial Polyester (PET) films. The Peel test shows that adhesion between Al films and PET depends on the heat setting conditions of the PET foils.In order to explain the observed differences in adhesion, ISS analyses were performed on the two surfaces obtained after peeling aluminium from the PET substrates. The Al/PET laminates were also studies by SIMS, RBS and TEM.ISS results show that the failure mechanisms differ for the two samples investigated. From the SIMS depth profiles, a lower sputtering rate is found for the sample presenting a lower adhesion, and RBS spectra show that the Al/PET interface is steeper for this sample. Also, marked differences in the Al grain sizes are observed by TEM: larger grains without preferred orientation are found on Al layers of poor adhesion.These results are discussed in view of elucidating the influence of the substrate properties on the metal/polymer adhesion.
Complementary data of RBS, NRA and SIMS on diffusion processes during friction in nitride implantation films
Authors: Pivin J. C. 
Published: May 2005

AbstractThe purpose of the present paper is to discuss the possibilities and limits of three analytical techniques—namely RBS, NRA and SIMS—in studies of the worn surfaces of thin films. The chosen examples are not the most simple since the obtainable data by means of each technique are limited by the nature of the films, riders and atmosphere of friction tests. Surfaces of Ti or Fe implanted with N ions were worn in air against steel or silica balls, using a tribometer specially conceived for further surface analysis. Different mechanisms of oxidative wear have been shown based on the data of the above techniques and punctual complementary analysis by XPS or TEM. They are a diffusion of oxygen in the bulk of TiN, FeN solid solutions, through short paths and cracks in Ti2N, TiN compounds. In any case, the N diffusion during friction, which has been often invoked to explain the durable wear resistance of implanted metals, has not been observed.
Microcharacterization of micron/submicron fly ash from a pulverized‐dry‐coal‐burning power plant
Authors: Hazrati Azar , Schrodt J. Thomas 
Published: May 2005

AbstractMicron/submicron fly ash particles from a pulverized‐dry‐coal‐burning power plant using an Eastern Kentucky bituminous coal, EKC no. 3, were subjected to physiocochemical microcharacterization analyses. These particles, when exposed to the beam of a transmission electron microscope, had their outer layers removed and as a result the appearance of their inclusions changed. Microchemical analysis by Auger electron spectroscopy (AES) revealed that splashed‐away layers were rich in sulfur and carbon with some coal‐originated, volatilized, condensed matter. The AES was used to analyze the composition of these layers and provide a thickness profile of the coating materials. Scanning electron micrographs revealed that the particles were partially hollow spheroids.
Sub‐micron molecular imaging. A viability study by time‐of‐flight SIMS
Authors: Briggs D. , Hearn M. J. 
Published: May 2005

AbstractThe possibility of sub‐micron imaging of molecular species on surfaces has been explored using a recently developed time‐of‐flight (TOF) imaging SIMS instrument which is equipped with a micro‐focused (∼500 Å) liquid metal ion source. Two model systems have been studied involving very thin (conducting) layers of organic materials on clean metals: a nonylphenol ethoxylate surfactant on gold and the peptide gly‐gly‐gly on aluminium.
Quantitation of coverages on rough surfaces by XPS: An overview
Authors: Fulghum Julia E. , Linton Richard W. 
Published: May 2005

AbstractSelected methods for the XPS quantitation of surface coverages are summarized with an emphasis on non‐planar samples with overlayers, e.g. powders of high surface area. Equations have been modified for uniform terminology and are presented based on a photoelectron spectrometer with an E−1 transmission function. Approaches which require a minimum of information from independent analytical techniques are given special consideration. Quantitative schemes discussed include calibration curves, surface sensitivity factors, exponential attenuation of bulk signals by overlayers, catalyst models, and the use of subshell twins or peak shape distortions related to photoelectron energy losses.
Results of a SIMS round robin sponsored by ASTM committee E‐42 on surface analysis
Authors: Hues Steven M. , Colton Richard J. 
Published: May 2005

AbstractThe results of a round robin involving the quantitative depth profile analysis of ion‐implanted boron in silicon by secondary ion mass spectrometry are reported. This study was a blind analysis; each participant was provided with three samples, a standard for which the implantation does was known and two other samples of unknown dose. The study compares the accuracy and precision of the quantitative analysis of boron in silicon, background signal levels, detection limits, dynamic range and sputter depth profile shapes obtained using fifteen SIMS instruments (fourteen commercial instruments manufactured by five different companies and one home‐built system). The quantitative SIMS analysis of boron in silicon, using similar standards, was found to have a relative standard deviation of approximately 10–12%, which also turned out to be the variation in sample homogeneity over the implanted samples, and a relative error of <10%. Comparison of sputter profile shapes shows a good degree of precision extending over six decades of signal intensity. The highest dynamic range of 6.1 × 105 and the best detection limit of 3.7 × 1020 atoms m−3 were found for analyses using the ‘mini‐chip’ method of v. Criegern and Weitzel. Results of a test concerning the lateral homogeneity of the depth distribution of the implanted species are presented and discussed.
XPS study of the Al/Pd interface
Authors: Légaré P. , Finck F. , Maire G. , Roche R. 
Published: May 2005

AbstractThe formation of the interface between a Pd polycrystalline substrate and Al deposits was followed by photoemission. Interdiffusion takes place readily and shows an evolution with time as well as under electron irradiation. The thickness of the mixed layer depends on the thickness of the Al deposit. The effect results in a narrowing of the Pd valence states.
Surface analysis of air pollutants by XPS: Problems and experiences
Authors: Kövér L. , Tóth J. , Schág J. B. , Borbély‐Kiss I. 
Published: May 2005

AbstractProblems and possibilities of air sampling (for surface analytical investigations) are discussed with particular attention to methods that fractionize particles by their sizes. Applications are illustrated by examples using metal and teflon surfaces as samplers. Biological samplers, such as leaves of different trees, proved to be applicable for XPS analysis and showed high sulphate content on their surfaces independent of the location of the three sampling sites. Independently of the methods and sites of air sampling a linear correlation has been found between the quantities of the surface carbon and nitrogen species characterized by their N 1s binding energies close to 400 eV, indicating surface bonds to carbon particles.
Reduction of charging in surface analysis of insulating materials by AES
Authors: Ichimura S. , Bauer H. E. , Seiler H. , Hofmann S. 
Published: May 2005

AbstractPractical methods are investigated to reduce the charging which is often observed during AES analysis of insulating samples with keV electrons. It is shown that the negative charge caused by electron beams with keV energy can be either avoided or considerably reduced by the use of an additional electron beam or by the supply of low‐energy (500 eV) positive ions. It is also reported and discussed that the state of reduced or vanishing charging obtained by both methods can be maintained for long periods of time.
Optimized ion beam raster for SIMS sputter depth profiling
Authors: Mitchell D. F. , Arlow J. S. , Phillips J. R. , Sproule G. I. 
Published: May 2005

AbstractA computer‐driven ion beam deflection system is described. This system allows custom tailoring of the ion beam raster to optimize SIMS depth profile performance. The ion beam is deflected to produce an approximately elliptical crater, which better matches the acceptance geometry of the ion extraction optics. A crater with a larger and more evenly flat bottom is produced by varying the resident time of the ion beam within the raster area, thus allowing for the collection of more signal with better depth resolution. This is accomplished by creating an array of equally spaced sputter points on the sample, taking into account the orientation of the ion gun and the SIMS optics with respect to the sample normal. The resident time of the ion beam along the crater perimeter is extended and the raster and mass spectrometer are synchronized. The improvement in performance is shown using a strain layer superlattice test sample 720 nm thick, consisting of 40 double layers of Si/Si–30% Ge.
Characterization of CuO–ZnO catalysts by X‐ray photoelectron spectroscopy: Precursors, calcined and reduced samples
Authors: Moretti G. , Fierro G. , Lo Jacono M. , Porta P. 
Published: May 2005

AbstractX‐ray photoelectron spectroscopy was applied to characterize CuO–ZnO catalysts (Cu/Zn atomic ratio ≥ 1) prepared by thermal decomposition at 350°C in air of hydroxycarbonate precursors obtained by the coprecipitation method at constant pH.For the precursors, the surface Cu/Zn atomic ratios have, within experimental error, the same values as that obtained by chemical analysis. This shows both a homogeneous dispersion of zinc in the zincian‐malachite solid solutions for the samples Cu/Zn = 92/8, 85/15 and 77/23, and a good interdispersion of the zincian‐malachite and aurichalcite phases in the 67/33 and 50/50 samples.In our calcined samples we find a strong interaction between the small oxide particles but no evidence of Cu2+/ZnO and Zn2+/CuO solid solutions. In the catalysts with low zinc loading, the ZnO phase (amorphous or with particles of a size < 40 Å) tends to cover the CuO particles. The catalysts with high zinc loading present the differential charging phenomenon due to the peculiar morphological situation of CuO and ZnO particles, as shown by the XPS measurements of samples supported on a biased sample holder.The reduction in situ under H2 at 135 and 200°C of these catalysts shows that Cu and Cu+ (Cu2O‐like) species are formed. Cu+ species are present even at high extents of reduction but the kinetics of the reduction and the relative amounts do not seem to be influenced by the presence of the ZnO phase. These findings are in agreement with our previous characterization with bulk techniques.A critical comparison with previous published papers dealing with XPS characterization of real and model catalysts is presented.
Quantitative AES and XPS investigation of magnetron sputtered TiNx films
Authors: Bender H. , Portillo J. , Vandervorst W. 
Published: May 2005

AbstractThe possibilities for quantitative compositional analysis of TiNx layers prepared by d.c. magnetron sputtering with Auger electron spectroscopy and x‐ray photoelectron spectroscopy are discussed. As an alternative to the AES quantification schemes reported in the literature, methods based on the ‘peak‐to‐peak‐minus‐x‐eV‐height’ and ‘factor analysis’ are examined. Different background subtraction methods are studied for the XPS quantification.