bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formal databases for surface analysis: The current situation and future trends
Authors: Powell C. J. 
Published: May 2005

AbstractEvaluated data are needed for surface analysis, just as for other measurements, so that analyses can be made reliably and effectively. Until recently, the principal sources of data were handbooks of spectra (mainly of elements) and review articles with values or equations for the parameters needed. This article describes three efforts to develop formal databases that can be incorporated into computer systems. Information is first given on a recently announced x‐ray photoelectron spectroscopy database, which contains over 13000 line positions, chemical shifts and splittings, together with associated software for searching by element, line type, line energy and other variables. Second, a summary is presented of a recent compilatation of evaluated elemental ion sputtering yields for applications in sputter depth profiling and secondary ion mass spectrometry. Finally, a description is given of a new database that is to contain Auger electron spectra and x‐ray photoelectron spectra; the database architecture is being designed also to accommodate depth profiles and the results of measurements by other surface analysis techniques.
Ion beam mixing and phase formation in NiAi multilayers studied by RBS and PAC
Authors: Weber Thomas , Lieb Klaus Peter , Uhrmacher Michael 
Published: May 2005

AbstractNiAl bi‐ and multilayers were irradiated with 300–900 keV Xe ions and analysed by Rutherford backscattering spectrometry (RBS) and the perturbed gamma‐ray angular correlation (PAC) method. As PAC measures the interaction of radioactive probe nuclei (111In) with hyperfine fields, it is sensitive to changes in the nearest‐neighbour surrounding induced by a phase transformation. The formation of the crystalline NiAL phase during irradiation was indeed detected by PAC; it was found to start at ion fluences below that required for complete mixing of the constituents. Similar results were obtained after 600 keV Ar irradiations. The interface mixing rate in NiAI bilayers due to 300–600 keV Xe ions was measured with RBS to be k = 4.5(3) ×104 Å4 at room temperature.
Auger parameter shifts in the case of the non‐local screening mechanism: Applications of the electrostatic model to molecules, solids and adsorbed species
Authors: Moretti Giuliano 
Published: May 2005

AbstractA simple electrostatic model is applied to predict and rationalize the auger parameter shifts in molecules, solids and adsorbed species. The model is valid in the case of the non‐local screening mechanism, i.e. when the screening of the core hole is due to the polarization of the nearest‐neighbour ligands (no charge transfer from the ligands to localized electronic levels of the atom with the core hole, as occurs with the main peak of the core‐ionized heavier 3dn transition metal ions or the light lanthanide ions). To good approximation it is shown that: (1) the Auger parameter shift is a function of the number, distance, electronic polarizability and local symmetry of the first‐neighbour ligands of the core‐ionized atom; (2) the dipole–dipole interactions can play a key role in determining the extent of the extra‐atomic relaxation energy and hence of the Auger parameter shift.
Adhesion between plasma‐treated cellulosic materials and polyethylene
Authors: Carlsson C. M. Gilbert , Ström GöRan 
Published: May 2005

AbstractFilter paper and greaseproof paper have been exposed to hydrogen or oxygen plasma. The paper surface composition was determined by ESCA measurements. The unmodified and modified papers then were laminated with polyethylene and the adhesive strength was measured. The hydrogen plasma treatment reduces the cellulose surface and forms low‐molecular‐weight degradation products. It is shown that the reduction of the cellulose surface has no influence on the adhesion, but the degradation products strongly decrease the adhesion. Oxygen plasma treatment increases adhesion, probably by removing low‐molecular‐weight wood resin from the surface and by forming covalent bonds across the interface.
Surface analysis at the sidewalls of VLSI patterns—limitations and capabilities of spatially resolved Auger electron spectroscopy
Authors: Hösler W. 
Published: May 2005

AbstractSpatially defined excitation by a confined primary electron beam is the basis of conventional scanning Auger microscopy. This method encounters a physical limitation in spatial resolution when it is used for the analysis of sidewall surface of micron‐ and submicron‐sized patterns on VLSI semiconductor devices. The limitation arises from scattered primary electrons, which drastically reduce the analytically usable spatial resolution whenever protruding features of the specimen topography are irradiated by the primary beam. A non‐conventional approach to improve the selectivity for surfaces of special orientation is presented, making use of the characteristic angular distribution of Auger electron emitted from surfaces. It is shown that by an appropriate modification of the angular spectrometer acceptance, the analytical resolution of sidewalls of VLSI patterns can be increased by more than one order of magnitude.
Quantitative aspects of ultraviolet photoemission of adsorbed xenon—a review
Authors: Jablonski A. , Wandelt K. 
Published: May 2005

AbstractUltraviolet photoelectron spectroscopy (UPS) is usually not considered to be a quantitative technique for the analysis of solid surfaces. However, careful examination of the He(I)‐induced 5p spectra of adsorbed xenon provides the basis for quantitative description of non‐uniform solid surfaces and/or adsorbed layers of xenon themselves. The shape, intensity and electron binding energy of the Xe 5p emission can be associated with the distribution, concentration and local surface potential of particular adsorption sites, respectively. Structural defects, such as steps, edges of evaporated metal islands and pores, can be characterized in this way. A particularly important application of the photoemission of absorbed xenon (PAX) is the determination of the coverage and average island size of metal adsorbates. The early stages of film growth and the thermally activated healing of surface roughness of such deposits can be followed quantitatively by PAX. Interesting quantitative information can also be obtained on the structure of the adsorbed xenon layer itself, such as the critical coverage for the two‐dimensional 2D Xe gas ↔ 2D Xe solid phase transition, the nucleation of three‐dimensional Xe clusters at defects and the presence and equilibrium topography of adsorbed Xe multilayers. These analytical possibilities of the PAX method are illustrated with applications to the Ru(001) surface, the epitaxially grown Ag film, the bimetallic Ag/Ru(001) system and the trimetallic and the trimetallic AgAu/Ru(001) system.
Surface composition of pentlandite under flotation‐related conditions
Authors: Buckley A. N. , Woods R. 
Published: May 2005

AbstractX‐ray photoelectron spectroscopy (XPS) and electrochemical techniques have been applied to the investigation of the surface oxidation of pentlandite. Photoelectron spectra indicate that the initial reaction on exposure to air is removal of iron from the pentlandite lattice to form a hydrated iron oxide overlayer and leave a metal‐deficient pentlandite in addition to a restructured nickel‐iron sulphide. Further oxidation resulted in some nickel being transferred to the oxide. In dilute acetic acid, the oxide layer was largely soluble. In basic media, the products were the same as in air but the reaction rate was greater. The voltammetric characteristics of pentlandite in solutions of pH 4.6, 9.2 and 13 were consistent with the XPS findings. Pentlandite behaved in a manner similar to that established previously for pyrrhotite indicating that the iron in pentlandite is preferentially removed on anodic oxidation to leave a metal‐deficient sulphide layer. There was evidence for the additional removal of nickel from the sulphide lattice. The formation of sulphate as also indicated on scans to high potentials in basic media.
SIMS studies of hydrogen diffusion through oxides on ZrNb alloy
Authors: McIntyre N. S. , Davidson R. D. , Weisener C. G. , Warr B. D. , Elmoselhi M. B. 
Published: May 2005

AbstractHydrogen migration has been followed through the thermally‐grown oxide on a Zr–2.5% Nb alloy. A secondary ion mass spectrometer, calibrated for deuterium, was used to measure the concentration as a function of depth into the film. Thin film oxide specimens, grown in steam to ∼1 μm thickness, were heated to 350 °C and exposed to deuterium gas at pressures ranging from 6 × 10−3 to 6 Pa and times from 30 to 870 min. Some irreversible uptake was detected for all exposures using SIMS. At low exposures, the shape of the deuterium concentration profile is Fickian and diffusion coefficients have been calculated. In this low‐exposure regime, the effect of temperatures between 280 °C and 350 °C on the diffusion equation has been measured. At longer exposures, the rate of deuterium ingress was sharply curtailed and a more complex diffusion profile was observed. Using Raman spectroscopy during a depth profile, the ZrO2 component of the oxide is found to change from a monoclinic–tetragonal mixture at the oxide surface to a primarily tetragonal oxide near the oxide/metal interface. Such changes in phase probably contribute to the complex deuterium diffusion kinetics observed during the longer exposures of the oxide film to deuterium gas.
AES and factor analysis study of cord‐oxidized brass layers and rubber‐to‐brass interface chemical composition
Authors: Kurbatov G. G. , Beshenkov V. G. , Zaporozchenko V. I. 
Published: May 2005

AbstractAuger electron spectroscopy (AES) and factor analysis (FA) were applied to study the chemical structure of oxidized brass layers and rubber‐to‐brass interface of tyre cords. The optimum requirements of sample preparation, instrument performance, data acquisition and analysis were determined to ensure accurate quantitative data. The elemental and chemical depth profiles of oxidized brass layers plated on steel cord and rubber‐to‐brass interface for standard vulcanization technology and after ageing obtained.
Estimates of peak areas and relative atomic amounts from wide‐scan XPS spectra
Authors: Turner N. H. 
Published: May 2005

AbstractIn an earlier investigation a polynomial method to estimate area and peak positions in wide‐scan XPS spectra was demonstrated with digital data (see N. H. Turner and A. M. Single, Surf. Interface Anal. 15, 215 (1990)). This method uses a density of points of about one per electron‐volt. It was found that in most of the cases studied the procedure gave area estimates that agreed reasonably well with determinations made from narrow‐region scans (which had a density of six to eight points per electron‐volt) with non‐linear least‐squares (NLLS) calculations. In addition, ratios between the areas of the various peaks were in reasonable accord with the NLLS determinations. However, these estimates were made with fairly intense peaks. In this study, area estimates were made by the polynomial procedure that included peaks with low intensity (i.e. surface contaminants or elements present in relatively small amounts). Also, approximations of the relative atomic amounts were made. These estimates then were compared to those from narrow‐region scan determinations that used the NLLS approach. Samples used included an insulator and conductors. In most instances the area ratios and the estimates of the relative atomic amounts from the polynomial procedure agreed to within a few per cent of values from the NLLS determinations. Poorer agreement was found in the estimates of adventitious carbon. This was due to both the comparatively small peak area and low relative intensity cross‐section for carbon. Also, the polynomial method did not work well when the adventitious carbon signal was comprised of several species. Much better agreement was obtained between the polynomial procedure and the NLLS approach with elements that have a relatively high photoelectron cross‐section.
Probing depth of soft x‐ray absorption spectroscopy measured in total‐electron‐yield mode
Authors: Abbate M. , Goedkoop J. B. , de Groot F. M. F. , Grioni M. , Fuggle J. C. , Hofmann S. , Petersen H. , Sacchi M. 
Published: May 2005

AbstractTwo series of experiments on well‐characterized systems were performed to examine the probing depth of soft x‐ray absorption spectroscopy (XAS) measured in total‐electron‐yield (TEY) mode. First we measured the Ni 2p3/2 absorption spectra of Ni(100) covered with Tb as a function of the overlayer thickness. Secondly we recorded the O 1s absorption spectra of Ta2O5 films produced by controlled anodic oxidatio of Ta foils as a function of the oxide thickness. The mean probing depth (MPD) was found to be much shorter than previously assumed (for O 1s, only 1.9 nm). The relative importance of those cascade mechanisms that lead to the electron current measured in TEY is discussed.
Optical second harmonic generation in reflection from silicon carbide films
Authors: Galeckas A. , Petrauskas M. , Willander M. , Wahab Q. 
Published: May 2005

AbstractSecond harmonic generation in reflection has been used to investigate the crystal properties of silicon carbide surfaces. By using a passively mode‐locked pulsed Nd3+: YAG laser the variation of the crystalline, polycrystalline and amorphous phase of silicon carbide at the surface has been investigated. The method is shown to be a sensitive and practical method to investigate the departure from perfect crystalline order at the surface.
Determining the thickness of very thin films of TiW
Authors: Tompkins Harland G. 
Published: May 2005

AbstractIn this work we show how to use ellipsometry to measure the thickness of TiW when the film thickness is ≤250 Å. Because the stoichiometry and microstructure of TiW depends strongly on the deposition parameters, the optical constants of TiW deposited in two different systems will not in general be the same. Accordingly, the optical constants of the film material are often not known. We show that the method is robust if a reasonable approximation to the optical constants is available, and we show how to obtain such an approximation. Auger electron spectroscopy is used to substantiate the conclusions.
p‐N junction depth profiling and conductivity type determination using Auger electron spectroscopy
Authors: Klyachko D. V. , Kozikov S. A. , Kriegel V. G. 
Published: May 2005

AbstractA novel method of p‐n junction determination is developed. The method is based on Auger line shift monitoring during Auger depth profiling of p‐n junctions in semiconductors using ion sputtering. The energy shifts of Auger lines are caused by surface cathodo‐electromotive forces—an analogue of surface photo‐electromotive forces but induced by electron bombardment. The possibilities and limitations of the method are studied by its application to p‐n junction depth profiling in Si, GaAs and InP and also in heterostructures made on the basis of AlGaAs alloys.The depth resolution of the method is found to depend on the sputtering dose needed to reach the p‐n junction and it is limited by diffusion of electrically active defects produced by ion bombardment. This limitation of the method makes it productive in evaluating the p‐n junctions located at submicron depths from the surface. For such junctions it provides better depth resolution than the electrical methods.
X‐ray‐induced beam damage observed during x‐ray photoelectron spectroscopy (XPS) studies of palladium electrode ink materials
Authors: Brown Norman M. D. , Hewitt Janet A. , Meenan Brian J. 
Published: May 2005

AbstractThe surface compositional characteristics of two palladium metal electrode inks, air‐dried on barium titanate (BaTiO3) dielectric ceramic substrates, have been studied using x‐ray photoelectron spectroscopy (XPS). It is found the exposure of the inks to the x‐ray beam during the time of analysis required for data acquisition causes surface damage. Changes in the C 1s and O 1s regions in particular, which reflect modifications to the organic, polymeric binder materials present in the inks, have been investigated as a function of x‐ray exposure time, incident ploton energy and beam power levels. Additional complexity in the C 1s spectral envelope that cannot be explained in terms of the expected contributing organic functionalities is observed. This is explained in terms of a difference in charging effects experienced by adventitious carbon species and those intimately associated with palladium metal centres.The degree of damage induced by the x‐ray beam under specific operating conditions has been compared also with that caused by exposure of the surfaces to an electron beam. Indications of the time scales and operating parameters for conducting XPS experiments on the unmodified surface, prior to surface degradation, are given.
Linearity in electron counting and detection systems
Authors: Seah M. P. , Tosa M. 
Published: May 2005

AbstractAn analysis is presented, with supporting experimental measurements, of the non‐linear effects in electron intensity measurements using channel electron multipliers (CEMs) in both the analogue amplification and pulse counting modes. It is shown that for Auger electron spectroscopy, where the CEMs may be used in the analogue mode, the output current should not exceed 0.8r% of the CEM wall current for the linearity to be maintained within r%. In the pulse counting mode, used more generally, simple dead time corrections are possible over a limited range of counting rates. This range is defined theoretically and experimental procedures are demonstrated to show how the range may be defined, and the necessary corrections made, to retain accurate linearity within 0.5%.
Composition of natural oxide films on polycrystalline tantalum using XPS electron take‐off angle experiments
Authors: Lecuyer Sylvie , Quemerais A. , Jezequel G. 
Published: May 2005

AbstractA model is presented to interpret the results of XPS electron take‐off experiments obtained for natural oxide films on polycrystalline tantalum. The high‐resolution spectrum of Ta 4f shows signals from Ta, TaO and Ta2O5. The angle variations of the intensity ratios Ta2O5/Ta and TaO/Ta show that the emitted signals came from three successive layers: Ta bulk, TaO at the interface and Ta2O5. The stoichiometry and thickness of the derived layers agree with the intensity ratio calculation obtained using a modelization where the interface is not homogeneous but made by large clusters of TaO (height 20 ± 4 Å, fractional coverage 0.56 ± 0.07). The surface is covered by 30 Å of Ta2O5, a value nearly equal to the sputtering result of Mathieu and Landolt.
Random uncertainties in AES and XPS: I: Uncertainties in peak energies, intensities and areas derived from peak synthesis
Authors: Cumpson P. J. , Seah M. P. 
Published: May 2005

AbstractWe develop equations for numerically evaluating random uncertainties in Auger and x‐ray photoelectron spectroscopies. First, the general statistical theorems involving the chi‐squared (χ2) distribution are clearly stated. These are applied to peak synthesis to determine the standard deviation uncertainties in quantities such as peak intensity, peak energy and peak width. General methods for their incorporation in new software are discussed. In the meantime, we suggest a new method for determining these uncertainty values using existing software provided by instrument manufacturers. These software packages typically give the χ2 value for the fit of a model spectrum to the experimental data. It is shown that (provided random errors dominate) a change in any adjustable parameter to its one standard deviation limit will cause the χ2 value for the fitting of all the other adjustable parameters to increase by unity. This provides a method which directly gives the standard deviation for each adjustable parameter.
Rotational Auger depth profiling of a GaAs/AlGaAs multilayer structure
Authors: Ericson R. E. 
Published: May 2005

AbstractA superlattice sample consisting of 200 alternating 5 nm layers of GaAs and Al0.45Ga0.55As was analyzed to explore some of the factors affecting depth resolution in rotational depth profiling by AES, including coincidence of sample rotation and probe beam axes, stability of analysis position and probe beam current density. Because of the periodic nature of the layers involved, it was possible to detect very small (< 2 nm) changes in surface topography. A mathematical model is proposed which explains the unusual features observed in the AES profile.
Size and support effects in the photoelectron spectra of small TiO2 particles
Authors: Fernández A. , Caballero A. , González‐Elipe A. R. 
Published: May 2005

AbstractThree different TiO2 samples in the form of bulk material, colloidal particles and small clusters supported on SiO2 have been studied by extended x‐ray adsorption fine structure (EXAFS), UV‐visible, transmission electron microscopy (TEM) and XPS. The different values of the Ti 2p binding energies and the Auger parameter of Ti found for each sample show that the photoemission processes in these oxide materials are influenced by size and support effects. A difference in the relaxation energy of −1.1 eV is found for the TiO2/SiO2 sample with respect to TiO2, which is attributed to an effect of the silica support.
Surface characterization (XPS and SIMS) of emersed polybithiophene electrodes
Authors: Morea Gemma , Sabbatini Luigia , West Robin H. , Vickerman John C. 
Published: May 2005

AbstractEmersed polybithiophene (pbT) films, doped at different levels with ClO4−, have been prepared by both discharging fully charged samples and charging fully discharged samples. The different strengths of two surface techniques, e.g. x‐ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS), have been fully exploited in the analysis of emersed pbT samples.XPS has been used to assess the relative atomic concentrations of species from substratum, dopant and, for the first time, solvent (acetonitrile). Curve analysis has been employed, where necessary, to discern between different chemical environments of the same atom. Different chemical environments for acetonitrile molecules have been observed in different samples.The higher surface sensitivity of static SIMS and variable‐angle XPS has been employed to distinguish between double layer and more deeply located mobile species.The participation of all mobile species (anions, cations and solvent molecules) to the charging‐discharging process and the direction of migration of them at the different stages of the process have been assessed and found to be in good agreement with previous reports.
Identification of the carbonaceous residues at nickel and platinum surfaces on the basis of the carbon KLL spectra
Authors: Lesiak B. , Jablonski A. , Palczewska W. , Kulszewicz‐Bajer I. , Zagórska M. 
Published: May 2005

AbstractInteraction of carbon compounds with transition metal surfaces results, under appropriate conditions, in the formation of a number of carbon‐containing species of different character. In the present work, the pattern recognition method (the k‐nearest neighbour rule) together with AES was applied to study the carbonaceous residues after adsorption of acetylene and ethylene at the surface of polycrystalline nickel and platinum. The above method identifies the residues by comparison to different samples of polyacetylenes. Identification is based on analysis of the KLL Auger spectra shape recorded for carbon atoms. As hypothetical oligomers, polyacetylenes with different conjugation lengths were chosen (7–105 Å). The applied method confirmed that ethylene and acetylene oligomerize at the nickel surface. Carbonaceous residues were recognized as the polyacetylenes with the longest conjugation lengths (105 Å). At the platinum surface the oligomerization process was also observed, but to a much smaller extent (average conjugation length equal to 15 Å).