bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ag, Ge and Sn reference samples for elastic peak electron spectroscopy (EPES), used for experimental determination of the inelastic mean free path and the surface excitation parameter
Authors: Gurban S. , Gergely G. , Menyhard M. , Adam J. , Adamik M. , Daroczi Cs. , Toth J. , Varga D. , Csik A. , Gruzza B. 
Published: October 2002

AbstractReference samples are needed for experimental determination of the inelastic mean free path (IMFP) of electrons by elastic peak electron spectroscopy (EPES). High‐quality (microcrystalline mirror) Ni reference samples were used for IMFP measurements. For surface excitation parameter experiments, new types of reference samples are needed. They should exhibit pronounced surface‐loss spectra, such as amorphous Ge (aGe), Sn and Ag. A new procedure is presented for their preparation. Microcrystalline Ag and Sn reference samples were deposited on highly polished (by Buehler alumina alpha micropolish 1C) brass (60% Cu, 40% Zn) substrates. Electrolytic deposition was used for Ag and for Sn and resulted in excellent surface quality. The average surface roughness rav was checked by scanning tunnelling microscopy or atomic force microscopy before and after Ar+ ion bombardment cleaning. Typical rav values were 4–6 nm for Ag, 3–4 nm for Sn and 2–4 nm for brass substrate. The aGe sample was deposited by magnetron sputtering or by evaporation in a high vacuum on an Si substrate. Its rav was 4–5 nm. The samples were studied by EPES/reflection electron energy‐loss spectroscopy, covering the 0.2–5 keV energy range, with the ESA 31 HSA electron spectrometer. The IMFP of Sn was determined by EPES. The surface excitation parameters for the Si, Ge and Sn samples were determined from their inelastic scattering cross‐section spectra. For Ag the surface excitation parameter was estimated by using the above reference samples. Copyright © 2002 John Wiley & Sons, Ltd.
XPS study of living tree
Authors: Shchukarev Andrei , Sundberg Björn , Mellerowicz Ewa , Persson Per 
Published: October 2002

AbstractX‐ray photoelectron spectroscopy (XPS) was used to study the distribution of elements and main wood components (cellulose and lignin) within the wood and at the bark/wood interface of a living hybrid aspen stem. The hybrid aspen was grown upright in a greenhouse and then tilted at ∼45° to induce tension wood formation and upright bending of the stem. The wood between the pith and the bark on the upper side of the tilted stem was analysed. Changes in the middle lamella/S1 layer chemical composition, which corresponded to the transition from normal wood produced during upright stem growth to tension wood produced upon stem tilting, were observed. Such changes were related to the lower lignin and higher cellulose/hemicellulose contents in the tension wood. A non‐uniform radial distribution of nitrogen (amino acids, proteins) within the stem was also noted. At the bark/wood interface the presence of inorganic elements (Ca, K and P) and a significant increase in nitrogen were found. The opposite wood side of the tree was enriched in lignin and fatty acids. It was shown that application of XPS imaging to a very rough surface of wood split allows the inhomogeneous lateral lignin distribution to be visualized. Copyright © 2002 John Wiley & Sons, Ltd.
Grain boundary segregation in Ni–Sb alloy polycrystals
Authors: Lejček Pavel , Rar Andrei , Hofmann Siegfried 
Published: October 2002

AbstractIn order to compare the grain boundary segregation of antimony and sulphur in bi‐ and polycrystals, the chemical composition of grain boundaries was studied by AES on fracture surfaces of polycrystalline Ni–Sb alloy (0.485 at.% Sb, 0.003 at.% S) samples annealed in the temperature range 773–1173 K. In contrast to the previously studied {133} bicrystals, dominant antimony segregation was observed at the grain boundaries of samples annealed in the above temperature range. By quantification of the AES results, the temperature dependence of grain boundary composition was determined and correlated with the Guttmann model of interfacial solute segregation in multicomponent systems. Consideration of various levels of grain boundary saturation and mutual interactions enabled the determination of the values of segregation enthalpy $(\Delta H^{0}_{Sb} = - 63\,\hbox{kJ mol}^{-1}, \Delta H^{0}_{S} = - 70\,\hbox{kJ mol}^{-1})$ and entropy $(\Delta S^{0}_{Sb} = - 20\,\hbox{J } (\hbox{mol}^{-1}\hbox{K}^{-1}), \Delta S^{0}_{S}= +12\,\hbox{J } (\hbox{mol}^{-1}\hbox{K}^{-1}))$ of both segregants. Extraordinarily high values of antimony concentration were detected at grain boundaries of bicrystals as well as polycrystals after annealing at high temperatures. It is highly probable that an extended two‐dimensional precipitation of nickel antimonides at grain boundaries occurs during the corresponding heat treatment. Copyright © 2002 John Wiley & Sons, Ltd.
Surface nanotextures on aluminium
Authors: Caicedo‐Martinez C. E. , Koroleva E. V. , Thompson G. E. , Skeldon P. , Shimizu K. , Habazaki H. , Hoellrigl G. 
Published: October 2002

AbstractChemical polishing and electropolishing of aluminium result in fine cellular textures of nanometre dimensions, which play a role in the electrochemical behaviour of aluminium and its response to further treatment processes such as conversion coating and anodizing. Concerning the latter, the surface texture is highlighted by porous anodic film growth for protection of the substrate. The influence of residual impurities and low additions of alloying elements on the development of the textures is investigated here for superpure aluminium (99.99%) and an Al–0.4wt.%Mn alloy, respectively. Complementary analytical approaches, including atomic force microscopy and transmission electron microscopy, disclose scalloped cellular textures comprising adjacent peaks and troughs, with a dependence on the grain orientation of the aluminium substrate. In addition to texture development, enrichment of copper impurity in the alloy occurs adjacent to the alloy/oxide film interface, as revealed by in‐depth elemental profiles generated by r.f. glow discharge optical emission spectroscopy. The absence of similar enrichments of iron and silicon in the alloy suggests that these elements are distributed mainly as fine segregates in the aluminium, unlike copper, which is in solid solution. At low alloying levels, manganese reveals limited enrichment and is also probably present mainly as segregates. The origin of the textures and their dependence on grain orientation are thus considered to be related to the presence and location of relatively high‐melting‐point elemental impurities in the alloy and their local electrochemical responses relative to the adjacent alloy surface. Copyright © 2002 John Wiley & Sons, Ltd.
In situ analysis using synchrotron radiation photoemission spectroscopy for initial oxidation of oxygen preadsorbed Si(001) surfaces induced by supersonic O2 molecular beams
Authors: Yoshigoe Akitaka , Teraoka Yuden 
Published: October 2002

AbstractBy means of synchrotron radiation photoemission spectroscopy we have performed in situ analyses for initial oxidation of oxidized Si(001) surfaces induced by supersonic O2 molecular beams. In the Si 2p, Si 2s and valence band photoemission spectra with an angle integrated mode, the O2 chemisorption processes induced by the O2 translational energy of 3.0 eV were clarified as a function of the exposure time. The Si2+ oxidation states, as well as Si1+, rapidly increased and then gradually decreased as a function of the O2 dose. However, Si4+ continued increasing gradually from the initial exposure. We found that the O2 incident energy of 3.0 eV directly induced oxidation in the backbond of the second Si layer. Copyright © 2002 John Wiley & Sons, Ltd.
Interdiffusion at TiO2/Ti, TiO2/Ti3Al and TiO2/TiAl interfaces studied in bilayer structures
Authors: Zalar A. , van Lier J. , Mittemeijer E. J. , Kovač J. 
Published: October 2002

AbstractEarly‐stage interfacial reactions were studied in three different heat‐treated oxide/metal bilayers (the oxide is amorphous (a) TiO2 and the metal is crystalline (c) Ti, c‐Ti3Al or amorphous a‐TiAl) by means of Auger electron spectroscopy (AES) depth profiling. The oxide/metal bilayers were sputter deposited onto smooth silicon substrates, covered with a TiN or Al2O3 thin‐film diffusion barrier. In order to prevent the supply of oxygen from the external atmosphere, selected samples were covered with an additional protective Si3N4 thin film. Reactions at the oxide/metal interfaces were induced by heating the samples in an argon atmosphere at a linear heating rate of 40°C min−1 between room temperature and different final temperatures (350–700°C). The composition and microstructure of selected samples were investigated by XPS, x‐ray diffraction (XRD) and transmission electron microscopy (TEM).Heating of the a‐TiO2/c‐Ti, a‐TiO2/c‐Ti3Al and a‐TiO2/a‐TiAl bilayers induced a decomposition of the a‐TiO2 layers, in association with diffusion and solid solution formation of oxygen in the corresponding metallic layers. In the early stage of the reactions, the presence of Al in the metallic layers resulted in a lower solubility of oxygen compared with a pure Ti layer. The beginning of interdiffusion at the a‐TiO2/c‐Ti interface was observed at ∼400°C and at the other two interfaces at ∼550°C. The temperature‐dependent effective diffusion coefficients were determined from the rate of increase of the interface width, as obtained in the oxygen depth profiles. The activation energies for oxygen diffusion from a‐TiO2 into the c‐Ti, c‐Ti3Al and a‐TiAl layers was found to be 1.5 eV (between 400 and 500°C) and 1.7 eV and 1.8 eV (between 550 and 650°C), respectively. Copyright © 2002 John Wiley & Sons, Ltd.
Organosilane self‐assembled monolayers formed at the vapour/solid interface
Authors: Sugimura Hiroyuki , Hozumi Atsushi , Kameyama Tetsuya , Takai Osamu 
Published: October 2002

AbstractSelf‐assembly of organosilane molecules at the vapour/solid interface under atmospheric pressure conditions was explored in order to form a monolayer on oxide‐covered silicon substrates. Three types of precursors were employed: n‐octadecyltrimethoxysilane (ODS: H3C(CH2)17Si(OCH3)3), n‐(6‐aminohexyl)aminopropyltrimethoxysilane (AHAPS: H2N(CH2)6NH(CH2)3Si(OCH3)3) and fluoroalkylsilane (FAS: heptadecafluoro‐1,1,2,2‐tetrahydro‐decyl‐1‐trimethoxysilane, F3C(CF2)7(CH2)2Si(OCH3)3). Characteristics of these self‐assembled monolayers (SAMs) formed at a temperature of 100–150°C were studied based on ellipsometry and x‐ray photoelectron spectroscopy. Chemical properties of the monolayers were characterized further by water contact angle and ζ‐potential measurements. The SAMs formed from ODS and FAS were hydrophobic so as to show water contact angles of >100°, whereas that of the SAM formed from AHAPS was ∼60°. ζ‐potentials and isoelectric points (IEPs) of SiO2 substrates covered with each of the SAMs were measured and compared with a naked SiO2 substrate. The IEPs of the SiO2 substrate covered with the ODS‐ or FAS‐SAM was pH 3.5–4.0, which was almost the same as those of polyethylene and polytetrafluoroethylene plates, whereas that of the naked SiO2 substrate was pH ∼2.0, as predicted from results on silica particles. In the case of the AHAPS‐SAM, its surface was positively charged under acidic conditions due to protonation of surface amino groups. Consequently, the AHAPS‐SAM‐covered substrate showed an IEP of pH 7.5–8.0. Copyright © 2002 John Wiley & Sons, Ltd.
MIES and UPS study of O‐predosed nickel surface reduction by H2 deposition
Authors: Fanjoux G. , Lescop B. , Le Nadan A. 
Published: October 2002

AbstractThe present study was aimed at investigating the reduction by hydrogen of an oxygen‐predosed nickel surface at high temperature (530 K) using metastable impact electron spectroscopy (MIES) and UPS (with He(I)) experimental techniques. Both techniques have allowed us to follow the evolution of the electronic structure of the valence band during H2 deposition. The work function variation seems to be related directly to the oxygen coverage of the surface and exhibits two stages: an induction period during which no reduction reaction occurs; a rapid reaction period corresponding to the reduction of oxygen. The reaction mechanism entails the formation of hydroxyl compounds but, owing to their thermal desorption at lower temperature in the form of water, no evident OH features have been observed in the MIES and UPS spectra.The 3d band intensity, measured at 0.5 eV under the Fermi level using UPS, increased linearly during H2 deposition. This evolution could correspond to that of bare Ni atoms in the three or four surface layers. On the other hand, evolution of the MIES signal taken at 5.7 eV under the Fermi level provided us with more accurate information about the evolution of the outermost layer of the predosed nickel surface during H2 exposure. Copyright © 2002 John Wiley & Sons, Ltd.
Photoelectron signal simulation from textured samples with modified surface composition
Authors: Vutova K. , Mladenov G. , Tanaka T. , Kawabata K. 
Published: October 2002

AbstractIn this paper we propose a mathematical model for calculating XPS intensity distributions from multi‐component textured samples with a step‐like distribution approximating the depth compositional profiles. The surface roughness is approximated using triangular prisms. Analytical expressions for calculation of angular photoelectron intensity distributions are given. The results obtained concern textured samples where the height of the surface roughness structures are 3–5 times greater than the ejection depth. The values of the altered layer thickness and the values of the emitted photoelectron's ejection depth are of the same order. This model is appropriate when studying the changes of compositional depth profiles in the range of the photoelectron ejection depth. Copyright © 2002 John Wiley & Sons, Ltd.
Application of self‐organizing maps (SOMs) to chemical spectral analysis of elements in the Periodic Table
Authors: Tokutaka H. , Obu‐Cann K. , Fujimura K. , Ikeda Y. , Yoshihara K. 
Published: October 2002

AbstractThis paper reports on the application of self‐organizing maps (SOMs) to chemical spectral analysis. The SOM method that was developed by Kohonen was first applied to information processing. Currently, it has been applied to some problems of chemical spectral analysis using AES, XPS and x‐ray diffraction data. Using a two‐dimensional SOM, it became clear that the items that are described qualitatively by linguistic expressions could be explained more quantitatively by the position of the spectral data on the SOM, together with a grey‐level expression. Also, the composition of an unknown sample can be determined very precisely by the SOM that has been constructed using the spectra from samples of known composition. Furthermore, this paper addresses the attempts to develop a SOM of all the elements of the Periodic Table. Currently, only 77 elements have been mapped out. Copyright © 2002 John Wiley & Sons, Ltd.
Use of XPS to follow the evolution of a solution/solid interface: SiMo12O404− acidic solution/GaAs interface
Authors: Debiemme‐Chouvy Catherine , Quennoy Anne , Etcheberry Arnaud 
Published: October 2002

AbstractIn some cases, XPS analysis can be used to determine the reactions that take place at a solid/solution interface. In this study, the behaviour of GaAs in contact with an acidic aqueous solution containing a Keggin‐type heteropolyanion—SiMo12O404−—was investigated on the basis of the XPS data. During immersion in the solution, a film composed of elemental As and partially reduced heteropolyanion develops on the GaAs surface. The chemical composition of the surface film indicates that at the GaAs/solution interface the heteropolyanion is reduced whereas GaAs undergoes an anodic dissolution process. The GaAs dissolution rate is proportional to the heteropolyanion concentration. At a given immersion time, the nature of the GaAs surface film is independent of the heteropolyanion concentration, whereas the As0/heteropolyanion ratio and the film thickness depend on this concentration. Moreover, the chemical composition of the film changes by exposure to air, as some elemental As atoms volatilize. Copyright © 2002 John Wiley & Sons, Ltd.
In situ measurements of surface homogeneity of optical parameters of weakly absorbing thin films
Authors: Spousta J. , Urbánek M. , Chmelík R. , Jiruše J. , Zlámal J. , Navrátil K. , Nebojsa A. , Šikola T. 
Published: October 2002

AbstractIn this paper an instrument based on combining the principles of both spectral and multiple‐wavelength reflectivity, designed by our group for in situ monitoring of the surface homogeneity of the thickness of weakly absorbing thin films, was tested in a series of ex situ and in situ experiments. The tests confirmed that it is a convenient tool for the in situ quasi‐real‐time monitoring of the surface homogeneity of the thicknesses of small‐area thin films (up to 1 cm2) during their etching and growth. Using this method, homogeneous growth of an SiO2 film with an average growth rate of 103 nm h−1 in one pilot point during deposition by ion beam sputtering of a quartz target was monitored in situ. On the other hand, the ion beam etching rate of the thermal SiO2 film was <3.3 nm min−1 and an enhanced roughness of the etched film in comparison to the initial one was observed. Copyright © 2002 John Wiley & Sons, Ltd.
Micro‐XPS analysis of slide‐tested TiN films with/without Cl+ implantation
Authors: Yoshitake M. , Thananan A. , Aizawaki T. , Yoshihara K. 
Published: October 2002

AbstractWe analysed the surface of TiN films (∼2 µm thick) with/without Cl+ implantation by scanning XPS. Both TiN films were subjected to a sliding test by a stainless‐steel ball, resulting in round, 150 µm wide scratches on the surface. We examined the difference in chemical composition and chemical state between the worn and the unworn surfaces. On the TiN film without Cl+ implantation, the primary compounds found were TiO2 and TiN with carbon contamination. The friction coefficient was ∼0.8 on this surface. The chemical compound on the worn surface was mainly Fe2O3 with a small amount of TiO2. This suggests that TiN is hard but not lubricative and that elements from the stainless‐steel ball adhered to the surface of the TiN film during the sliding test. On the TiN film with Cl+ implantation, the main compound found was TiO2, although we also observed a small amount of TiN. Furthermore, we detected a small amount of Cl, whose chemical state indicated binding with a metal component. The friction coefficient was <0.2 on this surface. The chemical compounds on the worn surface were TiN and TiO2, and no Fe was detected. We could clearly detect TiO2 on the surface of the stainless‐steel ball, therefore we concluded that oxidation is enhanced on Cl+ implanted TiN and that titanium oxide functions as a lubricant. During the sliding test, oxidation of the TiN film seemed to continue and titanium oxide was supplied continuously. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of reactive ion etching on amorphous carbon nitride films
Authors: Jiang Liudi , Fitzgerald A. G. , Rose M. J. , Gundlach A. M. , Cheung R. 
Published: October 2002

AbstractAmorphous carbon nitride (a‐C : N) films have been deposited by reactive direct current magnetron sputtering of graphite using N2 as the sputtering gas. In order to study the effects of dry etching on the deposited films, post‐treatment of the films has been performed by reactive ion etching in an argon plasma and an oxygen plasma, respectively. Fourier transform infrared (FTIR) spectroscopy and x‐ray photoelectron spectroscopy (XPS) have been used to study the chemical bonding structures in the films. We have found that although the FTIR results are very similar in all the samples, by comparing the XPS results from all the samples the relative ratio of the β‐C3N4‐like phase over the graphite‐like carbon–nitrogen phase in the films increased significantly after oxygen bombardment. This indicates that an oxygen plasma works effectively as an etchant of the graphite‐like phase in a‐C : N films. This process is conducive to the production of CN films that have a higher concentration of the β‐C3N4‐like phase. Copyright © 2002 John Wiley & Sons, Ltd.
Determining the angular admittance of a cylindrical mirror analyser
Authors: Watts B. , Thomsen L. , Dastoor P. C. 
Published: October 2002

AbstractRecent studies have demonstrated the need for the angular acceptance of a cylindrical mirror analyser (CMA) to be determined quantitatively. This acceptance probability function, with respect to the electron ejection angle, has not been reported previously. In this paper the angular acceptance function of a PHI‐550 double‐pass CMA has been determined quantitatively. A knowledge of this function makes it possible to extract some limited depth‐sensitive information from a standard CMA instrument without using a rotating aperture. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of the interface in rubber/silica composite materials
Authors: Salvi Anna Maria , Pucciariello Rachele , Guascito Maria Rachele , Villani Vincenzo , Intermite Luisa 
Published: October 2002

AbstractIn the rubber industry, especially tyre production, the most widely used elastomer is styrene–butadiene rubber (SBR) in which the styrene units generally are present at 25 wt.%. The unit repeats are random distributed along the macromolecular chains and the configuration of the butadiene units is mostly 1,4‐trans. The elastomer blends are mixed with fillers, acting as reinforcing agents, and the effect that silica particles have on their physical and mechanical properties is now well established. One of the most important parameters in determining the performance of such composite materials is the degree of adhesion at the rubber/silica interface. In this context, the interface characterization has been performed through a spectroscopic investigation (XPS/x‐ray‐induced Auger electron spectroscopy) in order to derive information from core‐level and Auger line chemical shifts. A series of composite rubbers have been examined by means of a detailed curve‐fitting procedure that allows the determination of intrinsic and extrinsic structures connected to each photopeak and the spectroscopic results compared with those of reference compounds. The changes in the C 1s lineshape and shake‐up region of the polymers and the reduced binding energies of silicon, oxygen and sulphur core lines have provided clear evidence of interfacial reactions. Moreover, the Auger parameters of silicon show systematic shifts that can be interpreted on a chemical state plot in terms of initial‐ and final‐state contributions and used for theoretical investigation of the local chemical environment. Copyright © 2002 John Wiley & Sons, Ltd.