bluuebunny/crossref_metadata_2025 huggingface dataset:
Adhesion between plasma‐treated cellulosic materials and polyethylene
Authors: Carlsson C. M. Gilbert , Ström GöRan
Published: May 2005

Filter 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

Spatially 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

Ultraviolet 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

X‐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

Hydrogen 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

Auger 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

In 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

Two 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

Second 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

In 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.
Analysis of zinc selenide by secondary ion mass spectrometry: Relative sensitivity factors and detection limits
Authors: Pachuta Steven J. , Smith Terry L.
Published: May 2005

SIMS relative sensitivity factors and detection limits are reported for seventeen elements in epitaxially‐grown ZnSe on GaAs, using oxygen and cesium primary ion beams. Analytical considerations necessary for obtaining the lowest detection limits are discussed.
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

A 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

The 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

An 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

A 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

We 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

A 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

Three 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

Emersed 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

Interaction 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).
Static SIMS imaging of the adsorption of diisobutyl dithiophosphinate on galena surfaces
Authors: Brinen J. S. , Reich F.
Published: May 2005

The spatial distribution of the molecular ion of diisobutyl dithiophosphinate on galena surfaces has been observed under static SIMS conditions using time‐of‐flight (ToF) SIMS measurements. The unequal spatial distribution observed is in accord with previous work which used fragment ions under non‐static conditions.
A comparison of Auger and STEM‐EDS quantification routines used in an investigation of intergranular segregation in long‐term aged nimonic PE16
Authors: Partridge A. , Tatlock G. J.
Published: May 2005

The grain boundary composition of long‐term aged Nimonic PE16 has been investigated by both Auger electron spectroscopy (AES) and scanning transmission electron microscopy‐energy dispersive spectroscopy (STEM‐EDS) analysis, and a detailed comparison made of the quantification routines developed for the two techniques.

The investigation showed that Mo, Cr and P segregate to the grain boundaries of the alloy during the standard pre‐service heat treatment, and that on extended ageing, at 450°C for 10 000 h and 550°C for 5000 h, the concentration of these elements at the grain boundaries increases. Furthermore, it was shown that there was good agreement between the two quantification routines developed to interpret the EDX and Auger spectra, allowing for the errors inherent in each method.
A common data processing system for surface analysis
Authors: Yoshihara K. , Yoshitake M. , Community Vamas‐Sca
Published: May 2005

In 1990 the Japanese contingent working within the VAMAS framework started to program software in Quick Basic for the IBM‐PC or NEC‐PC with MS‐DOS to translate spectral data acquired on different machines to the VAMAS‐SCA Standard Data Transfer Format and to process AES and XPS spectra in a standard manner. We call this software the Common Data Processing System.

The Common Data Processing System is designed to be a program to assess the data processing procedures proposed by scientists, to check a spectrum and to build both a spectra and a correction factor data bank. In this system, the spectral data acquired on different instruments and/or computers can be compared to one another.

The Common Data Processing System is not commercially produced. It should be perpetuated by scientists and engineers who have an interest in surface analysis.
Treatment of poly(ether ether ketone) (PEEK) surfaces by remote plasma discharge. XPS investigation of the ageing of plasma‐treated PEEK
Authors: Jama C. , Dessaux O. , Goudmand P. , Gengembre L. , Grimblot J.
Published: May 2005

The effect of a cold remote N2 plasma (CRNP) or N2 + O2 plasma (CRNOP) on poly(ether ether ketone) (PEEK) is studied. The amount of nitrogen or oxygen uptake and functionalities are determined by x‐ray photoelectron spectroscopy (XPS). After CRNP treatment, the N/C and O/C atomic ratios are 0.301 and 0.333, respectively. Nitrogen functional groups are not detected by CRNOP treatment, and the O/C atomic ratio is then 0.785. The ageing process of the treated PEEK surface in the open air is investigated in both cases. For CRNOP treatment the O/C atomic ratio decreases by carbonate function departure, whereas for CRNP treatment the total amount of nitrogen and oxygen graft atoms goes through a maximum after 1 h of air exposure.
Correction of Peak Shift and Classification of Change of X‐ray Photoelectron Spectra of Oxides as a Result of Ion Sputtering
Authors: Hashimoto Satoshi , Hirokawa Kichinosuke , Fukuda Yasuo , Suzuki Ken‐ichi , Suzuki Toshiko , Usuki Noriaki , Gennai Norio , Yoshida Sizuo , Koda Mitsuru , Sezaki Hiroshi , Horie Hiroshi , Tanaka Akihiro , Ohtsubo Takashi
Published: May 2005

Round‐robin experiments have been performed to correct binding energy shifts of XPS spectra for oxides by charge‐up which results from irradiation of x‐rays or ion sputtering and to determine criteria for the change of chemical state resulting from Ar ion sputtering. Al2O3, SiO2, MgO, TiO2 and NiO, in plate and powder form, were used for the experiments. We have revealed that the binding energy difference between the Al 2p (Si 2p or Mg 1s) line and the O 1s line gives a better correction for the measurements of Al2O3 (SiO2 or MgO) than that between the Al 2p (Si 2p and Mg 1s) line and the C 1s line. After Ar ion sputtering, TiO2 and NiO are reduced and new components appear in the XPS spectra. For Al2O3 and SiO2, the damage is induced by sputtering and the full width at half‐maximum (FWHM) values of XPS spectra increase, while MgO is unchanged. We have shown that the changes of oxides caused by ion sputtering depend on the change of free formation enthalpy and ionicity. We have also shown that both plate and powder samples are useful as standards to determine the binding energy from XPS spectra.
A round robin test of energies and chemical effects of Auger spectra from Fe, Ni and Al metals and their oxidized surfaces
Authors: Hirokawa K. , Ohtsubo T.
Published: May 2005

Auger spectra were measured using different pieces of the same specimen of Au, Fe, Ni, Al and their oxides by eight participating laboratories. The following points were found: by adjusting the specimen position with respect to the cylindrical mirror analyser using the elastic peak. Auger peak energy values obtained with each instrument were almost identical; Auger line shapes varied from instrument to instrument and from one operating condition to another; the variation of intensity ratio of LVV to LMM of Fe, Ni and their oxidized surfaces may be employed to identify chemical states.
Auger depth profiling of silicon dioxide on silicon: A factor analysis study
Authors: Sarkar M. , Calliari L. , Gonzo L. , Marchetti F.
Published: May 2005

An Auger sputter profile across the SiO2/Si interface is analysed by means of factor analysis (FA). As compared to conventional treatments of Auger data, more information is obtained in this way. In particular, the L2,3VV spectrum and the depth distribution of silicon atoms in an oxygen‐deficient situation with respect to the silicon dioxide stoichiometry are provided, thereby allowing a closer insight into the chemistry of this system.
SIMS depth resolution studies in AlxGa1−xAs using specially grown MBE samples
Authors: Houlton M. R. , Blackmore G. W. , Emeny M. T. , Whitehouse C. R. , Chew A. , Sykes D. E.
Published: May 2005

A quantitative analysis of the effect that the surface roughening due to oxygen ion bombardment has on the depth resolution of SIMS profiles has been carried out for the semiconductor alloys AlxGa1−xAs (x = 0, 0.175, 0.384 and 0.69) for a range of bombardment energies from 2 keV to 10.5 keV in two Cameca IMS 3F instruments. The loss of depth resolution is greater (and occurs at greater depths) with higher impact energies but occurs more rapidly with increasing x values. Good correlation is observed with the secondary ion signal intensity changes caused by surface roughening. No change of sample erosion rate is observed. No similar effect could be found with Cs, Ar, Xe, N or N2 bombardment.
Use of AES to determine sputter‐induced concentration profiles in Cu–Ni alloys
Authors: Roos W. D. , van Wyk G. N. , du Plessis J.
Published: May 2005

The difference in escape depth of Auger electrons of different energies was used to determine sputter‐induced concentration profiles in Cu‐Ni alloys. Alloys with Cu/Ni concentrations of 70/30, 50/50 and 30/70 at.% were bombarded with 2 keV Ar+ ions. After equilibrium has been reached, an AES spectrum for the alloy was recorded using a 12‐bit analogue‐to‐digital converter interfaced with a computer. Spectra for the pure elements, Cu and Ni, were recorded under identical conditions and were used to generate Auger spectra for the alloys that could be compared with the experimental data. The layer concentration values for which the best fit was obtained were used to construct a concentration profile. The results indicate a Cu‐enriched first layer followed by a depleted zone. It is concluded that the bombardment of Cu‐Ni alloys by 2 keV Ar+ ions leads to the segregation of copper and that AES can be used to determine sputter‐induced profiles if the necessary experimental precautions are taken.
Study of the oxygen treatment of high‐modulus polyethylene fibres
Authors: Woods D. W. , Ward I. M.
Published: May 2005

It has been found that three possible mechanisms can contribute to the improvement in fibre/resin adhesion when high‐modulus polyethylene fibres are subjected to oxygen gas plasma treatment. These mechanisms are surface oxidation, cross‐linking and surface etching. In this paper it is attempted to estimate the relative importance of these three mechanisms in the improvement of the interlaminar shear strength (ILSS) of polyethylene fibre/epoxy resin composites.

From a comparison of plasma treatment in oxygen gas and nitrogen gas it is concluded that surface oxidation makes a major contribution to the initial increase in ILSS for short treatment times. Examination of fibres cross‐linked by γ‐irradiation has demonstrated the effect of cross‐linking on ILLS independently of the surface oxidation and etching that accompany oxygen gas plasma treatment. Finally, scanning electron microscopy has shown the presence of micro‐surface cracks after relatively short plasma treatment times, and confirmed the unique cellular structures produced at long treatment times.

A comparison of the results from both batch and continuous plasma treatment processes for a range of melt‐ and gel‐spul fibres shows that the effect of oxygen plasma treatment for all these fibres are broadly similar in terms of ILSS, fibre strength and surface appearance.
Characterization of adhesive and coating constituents by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Part 1: Epoxy‐terminated diglycidyl polyethers of bisphenol‐A and propal‐2‐ol
Authors: Treverton J. A. , Paul A. J. , Vickerman J. C.
Published: May 2005

A series of epoxide resins typically used in adhesive and coating applications have been characterized by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Using thin‐film silver cationization, oligomers containing up to 16 bisphenol‐A groups were detected for the epoxide‐terminated diglycidyl polyethers of bisphenol‐A and propan‐s‐ol that comprise the bulk resins. For the higher molecular weight resins, the results indicate the additional presence of monoglycol‐, diglycol‐ and phenol‐terminated oligomers. For thicker film specimens, the spectra exhibit signals characteristic of the terminal epoxide and the bisphenol‐A components comprising the oligomer chains. Furthermore, the relative intensities of these diagnostic signals reflect the compositions of the epoxide resins in a quantitative manner.
Characterization of films of organofunctional silanes by ToF‐SIMS. Part II. Films of γ‐APS, AEAPS and FPS on cold‐rolled steel and cold‐rolled zinc substrates
Authors: van Ooij W. J. , Sabata A.
Published: May 2005

The structure, composition and thickness of thin films of various functional silanes formed on cold‐rolled steel or cold‐rolled zinc surfaces have been studied by high‐resolution time‐of‐flight SIMS and AES. The silanes were γ‐APS (aminopropyltriethoxy silane), AEAPS [N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxy silane] and FPS (perfluorinated propyltrimethoxy silane), which were deposited from dilute solutions by dipping or spin‐coating. Variables were the pH of the solution and the silane concentration. The objective of the studies presented here was to improve our understanding of the structure and orientation of silane films on metals, in view of possible applications of such coupling agents in areas where corrosion control and durable paint adhesion is required.
The SPLINT technique for sample preservation using liquid nitrogen transfer
Authors: Love C. J. , Cayless R. A. , Hazell L. B.
Published: May 2005

A simple, fast and convenient cryogenic method is described for avoiding post‐treatment oxidation and preserving the sample chemistry of iron during transfer from aqueous solution to ultrahigh vacuum (UHV) surface analysis instrumentation. It is recommended that others try this method and report on its wider applicability.
Valence band x‐ray photoelectron spectroscopic studies of carbonate, bicarbonate and formate interpreted by Xα calculations
Authors: Thomas Sajan , Sherwood Peter M. A.
Published: May 2005

The valence band and core‐level x‐ray photoelectron spectroscopy (XPS) of carbonate, bicarbonate and formate is reported. There is little difference between these ions in the core XPS spectra. The valence band spectra of carbonate and formate are similar (with some differences in relative intensities) and agree well with the spectrum calculated by multiple‐scattered‐wave Xα calculations. The valence band spectra of carbonate and bicarbonate are found to be identical at ambient temperature, despite the fact that the valence band spectra calculated by Xα calculations are predicted to be different. The carbonate valence band spectrum agrees well with the calculated spectra. When the bicarbonate data are recorded at liquid nitrogen temperature, however, the valence band region agrees well with the calculated spectra. These results indicate that bicarbonate is readily decomposed at ambient temperatures in normal XPS instruments, and that carbonate and bicarbonate can be distinguished by differences in the valence band region if the latter is prevented from decomposition by recording the data at low temperatures.
Scanning tunnelling microscope studies of sputtering
Authors: Wilson Ian H.
Published: May 2005

Experimental results are reported that improve our understanding of processes that initiate surface roughness from a single ion bombardment event.

The results are from a scanning tunnelling microscopy (STM) study of the ion bombardment of silicon at implantation energies. Also reported is an atom by atom analysis of a single sputtering event—8 keV krypton on a cleaved crystal of PbS. In both cases a very low ion dose was used to minimize the overlap of cascades. Recent results on the bombardment of gold and graphite will also be reviewed. The results show that every impact leaves its mark on the surface, indicating that surface roughening processes can be uncleated at the atomic level.
K‐Shell Auger transitions induced by Mo x‐rays
Authors: Kövér L. , Némethy A. , Cserny I. , Varga D.
Published: May 2005

For exciting K‐Auger transitions of elements with atomic number between 13 and 26, Mo x‐rays (Mo bremsstrahlung + Mo Lα,β) from a high voltage (max. 30 kV) source were used. High‐resolution K‐Auger spectra were measured by the help of a high luminosity hemispherical electron spectrometer. Spectral intensities obtained using the Mo x‐ray source are compared to the respective intensities measured using an Al anode and source parameters usual for electron spectrometers. The attainable gain in Auger yields is between 2 and 15 for most elements investigated and reaches a factor of 20.5 in the case of P KLL. Optimum conditions of K‐Auger excitation (regarding the atomic number region mentioned) are also discussed.

As an example for applications, the phosphorus K‐Auger parameter has been determined for GaP, taking an advantage of the presence of the P 1s (Mo Lα) photoelectron line in the spectra excited by Mo x‐rays. The higher analytical sensitivity, attainable by measuring Mo x‐ray‐induced P KLL Auger electrons compared to the sensitivity of the conventional XPS (Al Kα excited P 2p), is demonstrated in the case of a phosphoric compound (corrosion inhibitor) adsorbed on a polycrystalline Fe surface.
Development of an angle‐resolving electron spectrometer
Authors: Huang M. , Harland C. J. , Venables J. A.
Published: May 2005

An angle‐resolving electron spectrometer has been developed for use with an ultra high vacuum scanning electron microscope. A large cylindrical mirror analyser has been equipped with a parallel detection system for simultaneous recording of electron energy spectra and angle‐resolved images. Two different models have been developed to simulate the spectrometer. Angle‐resolved images and energy spectra of different electron emission functions can be simulated. The angle‐resolved images from amorphous samples were used to check the two simulation models and the performance of the spectrometer. Some initial results of applying the spectrometer on Ag/Ge(111) and Ag/α‐Ge are discussed.
New advancements in the theory of the Auger parameter: Applications to the characterization of small metallic particles
Authors: Moretti Giuliano , Porta Piero
Published: May 2005

A simple electrostatic model permits the calculation of the Auger parameter shifts of core‐ionized atoms in compounds with respect to the free atom in the gas phase. It is shown that the Auger parameter shift is a function of the number, distance, electronic polarizability and local geometry of the nearest‐neighbour ligands around the coreionized atom.

We have investigated the relationship between the Pd Auger parameter shifts and the nuclearity of Pd clusters entrapped in Y zeolites. It is shown that our model is useful to estimate this dependence. It is demonstrated that the Auger parameter shift depends not only on the nuclearity and geometry of the cluster but also on the nature of the heteroatoms in its close vicinity. This result could be explained by the influence of these heteroatoms on the electronic polarizability of the surface Pd atoms of the cluster.

The model has been applied also to the characterization of small copper clusters entrapped in A zeolite and supported on (0001) α‐alumina surfaces. In any case, we demonstrate that the screening properties of both metal bulk and clusters of very low nuclearity are very similar.
Dielectric loss function of Si and SiO2 from quantitative analysis of REELS spectra
Authors: Yubero F. , Tougaard S. , Elizalde E. , Sanz J. M.
Published: May 2005

A recently proposed model for quantitative analysis of reflection electron energy‐loss spectra (REELS) has been applied to evaluate the dielectric loss function of Si and SiO2 in the 4‐100 eV energy range, and to determine inelastic scattering properties for these materials for low‐energy electrons (500‐10000 eV). Appropriate trial energy‐loss functions (i.e. Im{1/ϵ}) are used and the best loss function is found from the criterion that a satisfactory quantitative agreement is obtained between the simulated and experimental inelastic scattering cross‐sections at several primary electron energies. The fact that the energy‐loss functions determined in this work agree remarkably well with optical data gives some confidence in the applied procedure. In addition, the effective inelastic mean free paths of the electrons as a function of the primary energy and the path travelled inside the medium have also been determined in terms of the respective energy‐loss functions.
Practical energy scale calibration procedure for auger electron spectrometers using a spectrometer offset function
Authors: Fujita Daisuke , Yoshihara Kazuhiro
Published: May 2005

In order to share AES spectral data and to develop an Auger spectra database, a practical and simple procedure for calibratiing the energy scale of Auger electron spectrometers has been developed. The procedure is based on the use of a spectrometer offset function, which enables transformation of measurements on the uncalibrated energy scale to a Fermi‐level‐referenced energy scale. In order to evaluate the effectiveness of this calibration method, a round‐robin test involving twelve spectrometers of various types has been performed. From a comparison of Ni L3VV and M3VV peak positions, it was found that the scatter among the measurements after calibration was reduced to 20–30% of the scatter before calibration.
Surface characterization with ion‐induced desorption and multiphoton resonance ionization
Authors: Ervin Matthew H. , Winograd Nicholas
Published: May 2005

It is known that high‐molecular‐weight, thermally labile molecules can be desorbed intact using keV ion beams. This knowledge has led to numerous applications of fast atom bombardment and secondary ion mass spectrometry (SIMS) by mass spectrometric detection of the desorbed ions. Here we show that these measurements can be enhanced significantly by using resonance‐enhanced laser ionization to softly ionize the neutral component of the desorbed flux. This experimental configuration can produce sensitivity improvements of several orders of magnitude over SIMS while adding a certain degree of selectivity to the ionization process itself. Examples of this performance will be presented using a wide variety of molecules, including polycyclic aromatic hydrocarbons, organic polymers, molecular salts and biologically important molecules. Results from model systems to complex samples are discussed, along with their implications for submicron molecular imaging using this technique.
Towards the ultimate limits of depth resolution in sputter profiling: Beam‐induced chemical changes and the importance of sample quality
Authors: Wittmaack K.
Published: May 2005

Recent progress in materials characterization by sputter profiling is discussed, with particular emphasis on a critical evaluation of the parameters that determine the depth resolution. The net effect of beam‐induced material transport and sputtering can be studied in a straightforward manner using abrupt doping distributions embedded in the matrix of interest, parallel to its flat surface. It is shown that the quality of the data that can be obtained with modern instruments is sufficient to identify lack of sample quality in terms of either surface flatness or abruptness of the doping distributions. Except for the presence of special artefacts, the depth resolution is always improved by using as low a bombardment energy as possible. The optimum angle of beam incidence depends on the crystalline structure of the sample as well as on the chemical identity of the primary ions. With oxygen primary ions a rather complex situation is encountered. Compared to inert gas ions, an improvement or a degradation in depth resolution may be achieved, depending on the impurity–matrix system under study. The merits of sample rotation are also discussed.
Scanning force imaging of organic multimolecular films
Authors: Cavalleri O. , Ricci D. , Rolandi R.
Published: May 2005

Scanning force microscopy (SFM) inspection shows that stearic acid deposited on a glass slide by evaporation of an organic solvent forms a layered structure. Scanning force microscopy images covering areas of a few square micrometres show a stack of bimolecular layers. Molecular resolution images of the layer surface shows ordered hexagonal patterns extending over areas as large as several unit cells. An accurate analysis of several images based on the evaluation of the Fourier transform made it possible to measure the unit mesh constant of the surface lattice with an accuracy of 1%. After samples are annealed slightly above melting temperature, the unit mesh constant decreases significantly, indicating a more compact arrangement of the molecules.
Acidity of the outer surface of dealuminated mordenites as studied by X‐ray photoelectron spectroscopy of chemisorbed ammonia
Authors: Remy M. J. , Genet M. J. , Lardinois P. F. , Notté P. P. , Poncelet G.
Published: May 2005

Chemisorption of ammonia on the acid sites located at the outer surface of dealuminated mordenites has been investigated by x‐ray photoelectron spectroscopy. The N 1s level of chemisorbed ammonia results from the overlapping of three components occurring near 402.4, 400.5 and 399.1 eV. From the N 1s binding energy of NH4+− exchanged mordenite and values reported in the literature for pyridine adsorbed on Brönsted and Lewis acid sites, the components at 402.5 and 399.1 eV are assigned to ammonia in interaction with Si–OH–Al framework groups and with Lewis acid sites, respectively. Based on XPS N/Al ratios and infrared results, the component at 400.5 eV is attributed to ammonia chemisorbed on silanol groups. The surface concentration of the three types of acid sites is estimated from the decomposition of the N 1s peaks. Evidence for the presence of surface extra‐framework Al in dealuminated mordenites is provided and the influence of these Al species on the outer surface acidity is discussed.
Atomic mixing, surface roughness and information depth in high‐resolution AES depth profiling of a GaAs/AlAs superlattice structure
Authors: Hofmann Siegfried
Published: May 2005

High‐resolution AES depth profiling of a GaAs/AlAs superlattice structure with 8.8/9.9 nm single‐layer thickness by sputtering with 1.0 keV and 0.6 keV Ar+ ions at an incidence angle of 80° resulted in optimum depth resolution values for 0.6 keV Ar+ ions of Δz = 2.0 nm for the low‐energy Al (68 eV) intensity profile and of Δz = 2.0 nm for the high‐energy Al (1396 eV) intensity profile. A simple model description of the influence of atomic mixing (w), surface roughness (σ) and Auger electron escape depth (λ) was applied to calculate the measured profiles. An excellent fit is obtained by a reasonable set of these parameters: for 0.6 keV Ar+ ion sputtering, w = 1.0 nm, σ = 0.6 nm, λ (Al 68 eV) = 0.4 nm and λ (Al 1396 eV) = 1.7 nm.
The formation of the copper/polyphenylquinoxaline interface: An HREELS study
Authors: Grégoire C. , Pireaux J. J. , Cros A. , Caudano R.
Published: May 2005

The interaction of copper with the surface of polyphenylquinoxaline is investigated with high resolution electron energy loss spectroscopy. The metal deposition is found to affect several features, in particular the elastic peak and the CH vibrational modes associated with the aromatic groups. Diffusion of copper to the bulk is observed upon thermal treatment.
The use of XPS valence band spectra in the study of plasma‐deposited polymeric films of tetramethyldisiloxane or hydroxyethylmethacrylate
Authors: Garbassi F. , Morra M. , Occhiello E. , Pozzi L.
Published: May 2005

Thin polymeric films were deposited from tetramethyldisiloxane (TMDSO) and hydroxyethylmethacrylate (HEMA) plasma. X‐ray photoelectron spectroscopy (XPS) and XPS valence band (XPS‐VB) analyses were performed to detect the effect of the deposition conditions on the structure of the plasma‐deposited films. In both cases XPS‐VB spectra were found strongly affected by the deposition conditions. Furthermore, XPS‐VB analysis can be used to obtain information on the structure and performances of these classes of plasma‐deposited polymer films.