bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical and electronic properties of Ag‐ and Cu‐TCNQ in polymeric matrix
Authors: Arena A. , Di Marco G. , Giorgi R. , Mezzasalma A. M. , Patanè S. , Saitta G. 
Published: May 2005

AbstractThe optical and electronic properties of the Cu‐ and Ag‐TCNQ salts determined by means of conventional spectrophotometry, reflection electron energy loss spectroscopy (REELS), and x‐ray photoelectron spectroscopy (XPS) measurements, are compared with those obtained for the copper and the silver TCNQ salts dissolved into a polyethyleneimine matrix. The optical properties of the obtained complexes differ substantially from those of the starting compounds, in particular, because of the interaction between the CuTCNQ and the polyethyleneimine, the state of oxidation of copper changes from Cu+1 to Cu+2. No meaningful changes are observed in the shape and peak position of the Ag 3d peaks of the silver‐based samples.
ARXPS and LEISS characterizations for chemically etched and ion‐bombarded GaAs(100) surfaces
Authors: Sullivan J. L. , Yu W. , Saied S. O. 
Published: May 2005

AbstractThe effects of chemical etching and noble gas ion bombardment on GaAs(100) surfaces were investigated by angular resolved x‐ray photoelectron spectroscopy (ARXPS) and low energy ion scattering spectroscopy (LEISS). The results show that at the As received GaAs surface, Ga oxide is the major component, resulting in a Ga concentration slightly higher than As. Chemical cleaning by hydrochloride acid (HCl(conc.) to H2O1:1) followed by solvent washing efficiently removed the oxide layer, but ARXPS showed a strong As enrichment occurs at the cleaned GaAs surface. Ion bombardment was carried out using 3 keV Ar ions with a beam current of 1 mA for 50 min. XPS results show that at steady state the ion‐bombarded GaAs surface is depleted in As (As/Ga ∼ 0.8), but ARXPS indicates an As increase at the very surface. This is further confirmed by Ne+ LEISS analysis, which shows the top layer As concentration is increased by 40% after ion bombardment. The results indicate that bombardment‐induced compositional changes are due to Gibbsian segregation.
Irradiation effects induced by reactive and non‐reactive low energy ion irradiation of graphite: An electron spectroscopy study
Authors: Gouzman I. , Brener R. , Cytermann C. , Hoffman A. 
Published: May 2005

AbstractThe effect of low energy Ar+ and N2+ irradiation of highly oriented pyrolytic graphite (HOPG) has been investigated by AES and XPS. Based on measurements of the C(KVV) Auger line shape before and after irradiation it has been found that a high degree of structural disorder is induced in the near‐surface region of HOPG. The production of defects induced by the irradiation process was established by the appearance of a shoulder at the high energy side of the C(KVV) Auger line. After Ar+ irradiation the shoulder is well defined and clearly visible in the Auger spectrum. However, after N2+ irradiation this shoulder is broader and its intensity is smaller than that observed after Ar+ irradiation. It is suggested that the defects created during the N2+ irradiation process are partly compensated by chemical bonding between implanted nitrogen and displaced carbon atoms. XPS measurements confirmed the existence of chemical bonds formed between the implanted nitrogen and carbon atoms.The effect of thermal annealing of the irradiated graphite was investigated up to 500 °C. At temperatures as low as 100 °C a decrease of the shoulder intensity was observed, whereas the desorption of the implanted Ar occurs at 300–400 °C only. These results suggest that the defects created by Ar+ irradiation are partially annealed. For N2+ irradiation, some nitrogen desorption occurs accompanied by a broadening and splitting of the N(1s) core‐level line. Also in this case, the shoulder intensity decreases with increasing the annealing temperature. It is suggested that partial annealing of the nitrogen‐implanted layer takes place. These results are of relevance for the understanding of the basic processes occuring during deposition of carbon nitride thin films by ion beam‐assisted methods.
Surface concentration modification of PtPd alloys by noble gas ion sputtering
Authors: du Plessis Johan , Taglauer Edmund 
Published: May 2005

AbstractThe surface concentration of three PtxPd1 − x alloys (x = 0.3, 0.5 and 0.7) under ion bombardment was studied as a function of ion species and ion bombardment energy for the noble gas ions He, Ne, Ar and Xe in the 0.5–1.25 keV energy range. The surface composition was measured by low‐energy ion scattering spectroscopy (ISS) and Auger electron spectroscopy (AES). It was observed that Pd is preferentially sputtered from the surface of these alloys (as corroborated by previous studies). This effect was found to be greatest for the lightest ion (He) and most pronounced for the lowest energies used. Only a very weak dependence of the surface concentration on the energy of the heaviest ion (Xe) was detected. Comparing ISS and AES (true surface and near‐surface information respectively), it was also found that Pd is depleted in the near‐surface region. The depletion is ascribed to radiation‐enhanced diffusion and segregation and it is shown how the overlaid contour mapping of ISS and AES intensities, as a function of diffusion coefficient D and segregation energy ΔG, may be used to determine the radiation‐induced diffusion coefficient D as a function of ion species and ion energy.
Recent aspects of surface infrared spectroscopy
Authors: Dumas Paul 
Published: May 2005

AbstractAmong the various classes of techniques used to probe solid surfaces, surface infrared spectroscopy has gained wide recognition for its ability to determine the chemical nature of surfaces and interfaces.Synchrotron infrared radiation has been demonstrated to be a source of high brightness in the far‐IR region, allowing determination of adsorbate‐substrate modes as well as frustrated vibrational modes of adsorbed molecules.Sum frequency generation, which uses both IR and visible pulses generated by lasers, and coupled at surfaces, allows the identification of species strictly located at the interface.Kinetic as well as dynamics measurements are a growing area of time‐resolved spectroscopy, using either spectrometers or lasers.
Surface acoustic wave resonance spectroscopy (SAWRS) as a novel technique to study surface phenomena
Authors: Boronin A. I. , Kvon R. I. , Prosvirin I. P. , Brezhnev V. N. , Ostanin V. P. , Seriklaev I. E. , Tupikov V. S. , Belyaev A. N. 
Published: May 2005

AbstractA new method is proposed for investigating surface phenomena based on the observation of the acoustic vibration modes of surface structures at high resolution. Experimental SAWR spectra can be obtained under a narrow frequency band excitation (Δω/ω ∼ 10−5) in a wide range (100 kHz–10 MHz). Application of this method to Ag(111) and Pt(100) single crystals reveals the existence of very narrow resonant acoustic vibration modes with Δω/ω ∼ 10−3–10−4 demonstrating strong anomalies in the phonon energy distribution function of solids. The behaviour of these anomalous peaks is very sensitive to surface structure and to the presence of adsorbates.
Extended fine structure in the secondary electron emission spectra of graphite and glassy carbon
Authors: Hoffman A. , Brener R. , Cytermann C. 
Published: May 2005

AbstractThe electron excited secondary electron emission (SEE) spectra of highly oriented pyrolytic graphite (HOPG) and glassy carbon (GC) were measured in the 0–150 eV electron kinetic energy range.For HOPG, the SEE spectrum was measured as a function of primary electron beam energy above and below the threshold for carbon core level 1s ionization. The SEE spectrum in the 0–70 eV range reflects high energy conduction band states, in agreement with band structure calculations and other spectroscopic techniques sensitive to the empty density of states. For electron kinetic energies above ∼ 70 eV the spectrum of HOPG displays a well defined structure which has not been studied previously. We found that the SEE fine structure in the low energy range up to ∼ 40 eV shows some dependence on primary electron energy, whereas for larger energies a much weaker dependence was found. It has been established that the SEE spectrum is strongly affected by low‐energy Ar ion irradiation of the HOPG surface. This result suggests that the SEE spectrum is very sensitive to crystal defects induced by the irradiation process. The lower‐energy range of the spectrum, up to ∼ 40 eV was found to be more sensitive to damage induced by the ion irradiation process than the higher range of the spectrum.For GC, the SEE spectrum in the 0–50 eV range is smeared out compared to that of HOPG. However, in the higher electron kinetic range some of the peaks measured for HOPG were also observed for GC. These results suggest that the lower‐energy range of the SEE spectrum is more sensitive to long‐range order, whereas the higher‐energy range of the spectrum reflects a shorter‐range order. It is suggested that SEE spectroscopy can be used as a very sensitive tool for the characterization of different carbon structures.
Local electronic structures in phosphorus oxyanions
Authors: Kövér L. , Némethy A. , Cserny I. , Nisawa A. , Ito Y. , Adachi H. 
Published: May 2005

AbstractThe local electronic structure around the core‐ionized phosphorus and oxygen atoms in solid phase Na3PO4, (NaPO3)n and Li3PO4 compounds has been studied by XPS and x‐ray excited Auger spectroscopy. Core level and valence band photoelectron spectra, as well as the O KLL Auger spectra have been measured using monochromated Al Kα excitation, while the high energy P KLV spectra have been excited using Mo‐x‐rays.From the similarity of the structures of the P KLV spectra it can be seen that the effect of the common tetrahedral symmetry is dominant while the effect due to the change of the cation is much smaller. This observation is supported by comparing the respective valence band photoelectron spectra to each other, and to the results obtained from cluster MO calculations.From the evaluation of the O KVV and O 1s spectra the oxygen Auger parameters have been derived and the 2p2p and 2s2p hole repulsion energies have been determined for each compound. The experimental values of the different Auger parameter shifts (Δα′, Δβ′) place the three oxyanions into the class of oxides, hydroxides and metallic anions instead of the class of non‐metallic anions and indicates the low electronic polarizability (similar to that of SiO2) of these phosphorus oxyanions.
The use of the anaerobic transfer electrochemical cell in the XPS investigation of polyaniline
Authors: Morea Gemma , Vickerman John C. , Walton John 
Published: May 2005

AbstractAnanaerobic transfer electrochemical cell, mounted on a side arm of the UHV chamber at 90° to the fast entry lock system of the XPS instrument was used to study the base‐salt transitions in the three main forms of PANI (leucoemeraldine, emeraldine and pernigraniline). The curve analyses of the N 1s peak, cross‐checked with relative atomic ratios of different species, are used to gain an understanding of the surface chemistry of the various PANI forms. Parallel analyses, using an ex situ cell, are performed. The results obtained highlight the air sensitivity of base leucoemeraldine and confirm the possibility of obtaining, using an ATE cell, electrochemical surfaces which, when analysed by XPS, display the surface chemical composition they are expected to have in the cell. Nevertheless this approach is not free from experimental difficulties especially as far as designing and mounting of the sample/electrode is concerned.
Weight function for linear least squares fit of binary CuNi and PtPd alloy Auger spectra
Authors: Roos W. D. , van Wyk G. N. , Du Plessis J. 
Published: May 2005

AbstractLinear least squares fits of an Auger spectrum of an alloy AB by a linear combination of elemental spectra A and B are usually performed without any weighting function Wi(E) as a function of the energy E. Too much significance is therefore attached to the constant (or peakless) segments of the spectrum. It is shown in this paper that the difference spectrum, i.e. (A — B) provides a suitable weight function for this type of fitting procedure. Two examples (CuNi and PtPd) are given where large overlaps occur for low energy peaks. The linear least squares fitting procedure is also extended to the general case of a non‐uniform bulk concentration which is illustrated and discussed.
True Auger spectral shapes: A step to standard spectra
Authors: Goto K. , Sakakibara N. , Takeichi Y. , Numata Y. , Sakai Y. 
Published: May 2005

AbstractWe have developed a novel cylindrical mirror Auger electron analyzer with the well defined electric field of 0.1% and the residual magnetic field of less than 1 mG. The CMA has a coaxial electron gun and the entrance angles are 42.3° ± 6°. The theoretically calculated energy resolution of 0.24% was obtained and the transmission was estimated to be 5.6%. This CMA can be used to obtain an absolute Auger electron yield with errors in peak heights of 5%, with an uncertainty in the energy position of 0.1 eV (or 0.01%), and with ghost intensities due to scattering of 0.1–0.2% for energies greater than 10 eV. Samples of polycrystalline gold, silver, and copper have been examined.
Influence of the elastic scattering cross‐section on angle‐resolved reflection electron energy loss spectra of polycrystalline Al, Ni, Pt and Au
Authors: Werner Wolfgang S. M. , Hayek Markus 
Published: May 2005

AbstractReflection electron energy loss spectroscopy (REELS) spectra for Al, Ni, Pt and Au were measured in the energy range 300–1500 eV for different scattering geometries. The energy dependence of the loss spectra was found to depend strongly on the shape and the magnitude of the elastic scattering cross‐section. This effect is extremely pronounced in the angle‐resolved spectra, but also persists in the angle‐integrated case. It was moreover observed that the relative intensities of the surface excitations in REELS spectra exhibit a similar dependence on the elastic scattering properties. These experimental observations are in good agreement with MC calculations accounting for elastic scattering through the differential Mott cross‐section and demonstrate that quantitative information regarding the inelastic scattering probability can only be extracted from REELS spectra if the exact shape of the elastic scattering cross‐section is accounted for and a quantitative description of surface excitations is available.
Correction of drift and slope distortions in STM image and scanner calibration
Authors: Yurov V. Yu. , Klimov A. N. 
Published: May 2005

AbstractSTM is a powerful tool for nanotechnology. But it is difficult to carry out correct measurements of distances and angles on the surface via STM image which is often distorted. Drift, slope of sample and indeterminate parameters of piezoscanner are considered as the origin of the STM image distortions. A special algorithm of STM scanning and correction of image of unknown atomic structures is suggested and tested. This algorithm makes it possible to measure three components of the drift velocity and two angles, characterizing the average slope of scanning surface. First, by using this algorithm, the STM calibration can be performed by a known surface structure (for example HOPG) even in the presence of drift. This enables determination of all the three piezoceramics constants of the STM piezoscanner and the deviation of the real scanner axes X and Y from orthogonality. Second, using such calibrated STM and the described algorithm, it is possible to obtain the real STM image and make measurements for unknown surfaces with atomic resolution without the distortions mentioned above. As have been proved, the error of interatomic distance measurements does not exceed 5% (or 0.1 Å) for any direction along the surface, even in the presence of a drift up to 0.4 Å s−1 and the sample slope angle up to 10º.
SiOx surface stoichiometry by XPS: A comparison of various methods
Authors: Alfonsetti R. , De Simone G. , Lozzi L. , Passacantando M. , Picozzi P. , Santucci S. 
Published: May 2005

AbstractThe surface stoichiometry of SiOx thin films (x = 1,…, 2) has been determined by means of x‐ray photoelectron spectroscopy using: (a) two well established methods involving the determination of the area of the O 1s and Si 2p core level peaks and the analysis of the Si 2p line shape, respectively, and (b) the method of the modified Auger parameter recently suggested. The agreement between the different approaches for determination of the stoichiometry of the films indicates the modified Auger parameter procedure as an easy, fast and very reliable method to ascertain the surface stoichiometry of SiOx films.
Simultaneous appearance of sharp and diffuse spots in LEED: Experiments and simulation for Si
Authors: Sakakibara Nobuyoshi , Hisada Yoshiyuki , Hattori Tadashi , Goto Keisuke 
Published: May 2005

AbstractThe LEED technique has been used to analyze HF‐treated actual Si(111) surface. The observed LEED pattern showed a three‐fold symmetrical sharp and hexagonal symmetrical diffuse pattern that is considered to reflect disordered structures in the top surface of the Si. The pattern was compared with a three‐dimensional optical diffraction simulation. In the optical simulation, it was assumed that terminating hydrogen atoms at the Si(111) surface are so arranged that mono‐hydride and tri‐hydride structures are distributed at random. Then hexagonal symmetrical sharp spots and diffuse spots appeared simultaneously. The existence of Si—H, Si—H2, and Si—H3 bonds was confirmed by infrared (IR) spectroscopy.
Quantitative GDOS analysis of oxide films on steels
Authors: Suzuki S. , Suzuki K. , Mizuno K. 
Published: May 2005

AbstractA method for the quantitative analysis for oxide films on steels by means of glow discharge optical emission spectrometry (GDOS) was investigated. Effective optical emission yields for analysed elements were determined by measuring the emission intensities and sputtering rates of standard samples during discharging under constant conditions. The chemical composition in oxidized samples was obtained from the emission intensities and the effective emission yields, while the sputtered depth was calculated from the emission intensities and effective densities of elements. From measurements of the sputtering of magnetite the effective density for oxygen was estimated as 1820 kg m−3. It was shown that GDOS can be used to determine the quantitative composition and the thickness of the oxide layers on steels.
Recent progress of thin film technology in the automobile industry
Authors: Taga Yasunori 
Published: May 2005

AbstractThis review paper first describes a new concept of the thin film process in material synthesis on the basis of ion‐surface interaction during deposition. Some examples of practical applications of various thin films to automobiles are then given. They include optical thin films, sensor films and surface modification by ion implantation and thin film techniques. Finally, further challenges to applications of thin films to the automobile industry are discussed.
In‐depth homogeneity of vapour deposited multicomponent thin films
Authors: Jehn Hermann A. , Huber Eberhard , Hofmann Siegfried 
Published: May 2005

AbstractIn many fields of advanced technology, thin film properties are fitted to specific requirements by the codeposition of alloying additives. In particular the physical vapour deposition (PVD) techniques allow an almost unlimited range of film composition. The sources can be single or multiple targets. Due to the technical performances of the deposition process, an inhomogeneous in‐depth distribution of the elemental concentration may occur. In the present paper the concentration distribution of multicomponent thin films is discussed using ternary nitride coatings as an example ((Ti, Cr)N, (Ti, Pd)N, (Cr, Pd)N). Oscillating elemental distribution is observed due to the sample rotation during film deposition. The laminate thickness depends on the flux density and rotation speed governing the local growth rate and can range down to few nanometres. The ternary nitride films were deposited by the hollow cathode discharge electron beam evaporation and the magnetron sputter technique, respectively, and were characterized by Auger electron spectroscopy (AES) and glow discharge optical spectroscopy (GDOS).
Ex situandin situcharacterization of surfactant monolayers adsorbed on nonmetallic substrate by infrared reflection spectroscopy
Authors: Mielczarski Jerzy A. 
Published: May 2005

AbstractThe adsorbed (self‐assembled) submonolayers and monolayers structure, orientation and chemical interaction at the interface of nonmetallic (semiconductor) have been studied by infrared reflection spectroscopy. The experimental data collected fromin situandex situmeasurements have led us to propose mechanisms of interaction between surfactants and surfaces. The reflection spectra of the adsorbed layers on different substrates recorded at different angles of incidence and for two polarizations are an excellent source of information about the composition and structure of the layers. The major problem is the interpretation of the recorded reflection spectra which are modified by optical effects, compared with the corresponding transmission spectra of the same layer on a transparent support. The developed method makes it possible to interpret the experimental reflection spectra on the basis of spectral simulation data. It is shown that it is possible to obtain reliable chemical and structural information on the adsorption layer and distinguish it from other observed spectral modifications due to optical effects. The high sensitivity of this method permits the investigation of ultrathin layers (submonolayers). By combination of the simulated and experimental data, the orientation angles of the transition moments of the major infrared bands and the thickness of the adsorption layers were evaluated.
In situ quantitative soft x‐ray spectrometry of thin films synthesized by DC sputtering
Authors: Legrand P. B. , Dauchot J. P. , Wautelet M. , Hecq M. 
Published: May 2005

AbstractSpectrometry of the soft x‐ray emitted by the growing film or its substrate during sputtering is used to monitor the film synthesis: determination of native oxide on the substrates, film stoichiometry versus experimental conditions, control of oxygen content during nitride synthesis, etc. Quantitative data can be obtained by using a simple exponential profile for the ionization function.
Determination of the depth resolution of Auger electron spectroscopy depth profiles of anodic barrier oxide films on differently pretreated aluminium substrates
Authors: De Laet J. , De Boeck K. , Terryn H. , Vereecken J. 
Published: May 2005

AbstractThe virtual interface width in AES sputter depth profiles of amorphous anodic oxide coatings on aluminium is investigated. Even when the physical film–substrate interface is relatively sharp, considerable deterioration of the depth resolution may be caused by sputter‐induced roughness if sputtering conditions or the sample quality are not chosen properly. The effects of the oxide film thickness, choice of sputter angle and initial substrate roughness on the appearance of the interface width are investigated. A systematic study of the influence of Zalar rotation on the depth resolution is presented. It is concluded that long sputter times, due to film thickness or grazing sputter angles, and initial surface roughness cause a deterioration of the depth resolution. Zalar rotation generally improves the depth resolution for amorphous films, and is particularly indicated for the analysis of very rough samples. The sputter rate of amorphous films however, is insensitive to the use of Zalar rotation.