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[en] Photoemission spectroscopy (PES) has been used widely to study the electronic structure of valence and core levels. However, conventional PES is surface-sensitive. To probe the interface and bulk properties of materials, hard X-ray photoemission spectroscopy (HXPES) has received increasing interest in the last decade, because of the deep probing ability of photoelectrons with higher kinetic energies (2-10 keV). Recently, a HXPES system was developed at the Canadian Light Source, using the high-energy version of a R4000 electron analyzer-based spectrometer connected to a medium-energy beamline, the soft X-ray microcharacterization beamline (SXRMB). Excellent performance of the beamline and the spectrometer is demonstrated herein using Au Fermi and 4f core lines; and the controlled probing depth of HXPES at SXRMB is demonstrated by tuning the photon energy (2-9 keV) in the study of a series of SiO2/SiC multilayer samples. Combined with the high-resolution X-ray absorption spectroscopy available at the SXRMB, the HXPES offers a powerful nondestructive technique for studying bulk properties of various materials. (author)
[en] Resistance switching phenomena in an amorphous Ni-Ti-O film were investigated. Very clear bipolar resistive switching characteristics were observed with good reproducibility. Stable retention and on/off pulse switching operation was demonstrated. An analysis of x-ray photoelectron spectroscopy of the Ni-Ti-O film provided a clue that the observed unusual bipolar resistance switching in the film is due to a microscopic change in the Ni-O and Ti-O binding states at the Ni-Ti-O film/electrode interface.
[en] Highlights: • The need by industry for small area analysis spurred the advent of the XPS Microprobe. • The Microprobe design allows for rapid x-ray induced secondary electron imaging. • Small areas of interest can quickly be located and analyzed. • Industrial applications include varied types of failure and contamination analyses. • Multipoint depth profiles can be obtained in one acquisition with one sputter crater. - Abstract: We will review the evolution of x-ray photoelectron spectroscopy (XPS / ESCA) instrumentation and applications that led to the development of the scanning XPS microprobe, describe its unique capabilities, and how they have impacted the use of XPS for industrial applications.
[en] X-ray photoelectron spectroscopy (XPS), also called electron spectroscopy for chemical analysis (ESCA), is widely used both in basic research and in analysis of materials, particularly in surface analysis. Using XPS we can obtain information on the elemental surface composition (except for H and He), and the electronic structure of the materials involved. This paper will briefly review the principle of XPS, basic qualitative and quantitative data analysis methods, and some application examples. (authors)
[en] In this study, the effects of corona plasma process on the dyeability and certain physical properties of woolen fabric were investigated. For this purpose, acid and 1.2 metal complex dyes, which are the most applicable dyes in the wool market were used. The patterns were examined to assess their dyeability, wettability, pilling resistance, alkali solubility, and strength values. The surface morphology and chemical structures were tested by X-ray photoelectron spectroscopy and alkali solubility analyses and also scanned by electron microscopy. Hydrophility indexes of the dyes that were used were determined. With the results of the experiments, their hydrophobic index is of vital importance, which is a factor for plasma efficiency on color depth. By using plasma treatment on woolen fabric, it is achievable to get a product with high hydrophility and pilling resistance values, dyeability, and less burdened dyeing bath.
[en] XAFS and X-ray Photoelectron Spectroscopy (XPS) are element specific techniques used in a great variety of research fields. The near edge regime of XAFS provides information on the unoccupied electronic states of a system. For the detailed interpretation of the XAFS results, input from XPS is crucial. The combination of the two techniques is also the basis for the so called core-hole clock technique. One of the important aspects of photoelectron spectroscopy is its chemical sensitivity and that one can obtain detailed information about the composition of a sample. We have for a series of carbon based model molecules carefully investigated the relationship between core level photoelectron intensities and stoichiometry. We find strong EXAFS-like modulations of the core ionization cross sections as function of photon energy and that the intensities at high photon energies converge towards values that do not correspond to the stoichiometric ratios. The photoelectron intensities are dependent on the local molecular structure around the ionized atoms. These effects are well described by molecular calculations using multiple scattering theory and by considering the effects due to monopole shake-up and shake-off as well as to intramolecular inelastic scattering processes.
[en] X-ray photoelectron spectroscopy (XPS) is a quantitative surface analysis technique used to identify the elemental composition, empirical formula, chemical state, and electronic state of an element. The kinetic energy of the electrons escaping from the material surface irradiated by an x-ray beam produces a spectrum. XPS identifies chemical species and quantifies their content and the interactions between surface species. It is minimally destructive and is sensitive to a depth between 1-10nm. The elemental sensitivity is in the order of 0.1 atomic %. It requires ultra high vacuum ((Formula presented.) Pa) in the analysis chamber and measurement time varies from minutes to hours per sample depending on the analyte. XPS dates back 50 years ago. New spectrometers, detectors, and variable size photon beams, reduce analysis time and increase spatial resolution. An XPS bibliometric map of the 10 000 articles indexed by Web of Science identifies five research clusters: (i) nanoparticles, thin films, and surfaces; (ii) catalysis, oxidation, reduction, stability, and oxides; (iii) nanocomposites, graphene, graphite, and electro-chemistry; (iv) photocatalysis, water, visible light, and TiO2; and (v) adsorption, aqueous solutions, and waste water. (author)
[en] Analytical models for the determination of thin film growth modes were developed on the basis of the simultaneous multilayer (SM) growth model. The models take into account up-step and down-step diffusion, enabling quick identification of the growth modes from experimentally obtained spectroscopic data. We tested the models by applying them to growth data from the literature that had been recorded via Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and low-energy ion scattering (LEIS). We discuss the applicability of the new analytical models in comparison with the diffusion-corrected simultaneous multilayer (DCSM) model
[en] X-ray photoelectron spectroscopy (XPS, ESCA) is an ideal tool for identifying differences in surface chemistry. In the past, it has lacked the spatial resolution as well as the performance of elemental or even chemical state imaging, to be of significant use in detecting most microscopic surface phenomena. The recent development of improved micro- or small spot-XPS systems with near-micron spatial resolution as well as outstanding chemical state image performance has opened up a significant opportunity to undertake more detailed studies of micro-structured or micro-patterned surfaces or technical samples with locally distributed impurities. The introduction of a new detector type, the delay-line detector (DLD), to XPS-equipments allows for the first time the acquisition of quantifiable XPS images. This study is intended primarily to explore the capabilities of quantitative ESCA-imaging with respect to the possibilities and limits
[en] Highlights: • Optimal tuning parameters for three parameter choice methods were sought. • Two profile shapes and three regularization orders were used. • Compromise tuning parameter values for 1st order regularization are suggested. - Abstract: Composition depth profiles were extracted from simulated ARXPS data using regularization, with the regularization parameter determined by three different methods (Robust GCV, Modified GCV, and the Discrepancy Principle) that require tuning parameters. For each method, the optimal tuning parameter was determined for two input profile shapes, three Tikhonov regulators (0th, 1st, and 2nd order), and data noise ranging from 1% to 9%. Although universally applicable optimal tuning parameters were not identified, it was found that certain values could consistently produce acceptable results for the input profiles used in this study