https://www.surfacesciencewestern.com/wp-content/uploads/2012/01/ass11_biesinger.pdf

Resolving surface chemical states in XPS analysis of first row transition metals, oxides and hydroxides: Sc, Ti, V, Cu and Zn

Chemical state X-ray photoelectron spectroscopic analysis of copper species is challenging because of the complexity of the 2p spectra resulting from shake-up structures for Cu(II) species and overlapping binding energies for Cu metal and Cu(I) species. This paper builds upon and extends previously published X-ray photoelectron spectroscopy curve-fitting and data analysis procedures for a wide range of copper containing species. Steps undertaken include the following: (i) an examination of existing Cu 2p3/2 main peak and Cu 2p3/2 – Cu L3M4,5M4,5 Auger parameter literature data, (ii) analysis of a series of quality standard samples, (iii) curve-fitting procedures for both the Cu 2p3/2 and the Cu L3M4,5M4,5 spectra (as well as associated anions), (iv) calculations that determine the amount of Cu(II) species in a mixed oxidation state system, (v) calculations and necessary data for thin film mixed oxide/hydroxide thickness measurements, and (vi) a presentation of literature and standard sample values in a Wagner (chemical state) plot. Copyright © 2017 John Wiley & Sons, Ltd.

Advanced analysis of copper X-ray photoelectron spectra

Surface composition analysis by low-energy ion scattering

We demonstrate supercontinuum generation in a highly nonlinear As2S3 chalcogenide planar waveguide which is dispersion engineered to have anomalous dispersion at near-infrared wavelengths. This waveguide is 60 mm long with a cross-section of 2 µm by 870 nm, resulting in a nonlinear parameter of 10/W/m and a dispersion of +29 ps/nm/km. Using pulses with a width of 610 fs and peak power of 68 W, we generate supercontinuum with a 30 dB bandwidth of 750 nm, in good agreement with theory.

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Supercontinuum generation in dispersion engineered highly nonlinear (γ = 10 /W/m) As_2S_3 chalcogenide planar waveguide

Fe-based bulk metallic glasses: Glass formation, fabrication, properties and applications

Chalcogenide glasses have attracted considerable attention and found various applications due to their infrared transparency and other optical properties. The As–S–Se chalcogenide glass, with its large glass-formation domain and favorable nonlinear property, is a promising candidate system for tailoring important optical properties through modification of glass composition. In this context, a systematic study on ternary As–S–Se glass, chalcogen-rich versus well-studied stochiometric compositions, has been carried out using three different techniques: Raman spectroscopy, x-ray photoelectron spectroscopy, and extended x-ray absorption fine structure spectroscopy. These complementary techniques lead to a consistent understanding of the role of S∕Se ratio in chalcogen-rich As–S–Se glasses, as compared to stochiometric composition, and to provide insight into the structural units (such as the mixed pyramidal units) and evidence for the existence of homopolar bonds (such as Se–Se, S–S, and Se–S), which are the ...

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Role of S /Se ratio in chemical bonding of As-S-Se glasses investigated by Raman, x-ray photoelectron, and extended x-ray absorption fine structure spectroscopies

To establish the validity of various proposed structural models, we have investigated the structure of the binary As{sub x}Se{sub 100-x} chalcogenide glass family (x{<=}40) by high-resolution x-ray photoelectron spectroscopy From the composition dependence of the valence band, the contributions to the density of states from the 4p lone pair electrons of Se and the 4p bonding states and 4s electrons of Se and As are identified in the top part of the band The analysis of Se 3d and As 3d core-level spectra supports the so-called chain crossing model for the atomic structure of Se-rich As{sub x}Se{sub 100-x} bulk glasses The results also indicate small deviations ({approx}3-8%) from this model, especially for glass compositions with short Se chains (25<x{<=}40) For example, the presence of As-As homopolar defect bonds in the stoichiometric As{sub 40}Se{sub 60} and of Se-Se-Se fragments in a glass with composition x=30 is established

Structure of Se-rich As-Se glasses by high-resolution x-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy (XPS) has revealed physical and chemical structure differences between aluminum and boron substituted sodium silicate glasses, Na2O · xR2O3 · (3 − 2x)SiO2, prepared by a melt quench method, where R = Al or B, and x = 0, 02, 04, 06, 08, 1 The structure of sodium aluminosilicate (SAS) glasses deduced from the analysis of XPS data is found to agree with the four-coordinated aluminum structure model with Na balancing the local charge The structure of sodium borosilicate (SBS) glasses is mostly consistent with Bray's model with the need to consider a ‘contending factor’ for Na Sodium is not fully ionized as often assumed Its ionicity increases in both SAS and SBS glasses with increasing Al/B substitution Net charge on atoms according to Pauling's model has been calculated as a guidance in analyzing the XPS spectra

X-ray photoelectron spectroscopy of Al- and B-substituted sodium trisilicate glasses

High-resolution X-ray photoelectron spectroscopy is used to identify the mechanism of X-ray-induced Ag diffusion into Ge30Se70 chalcogenide glass thin films, which are prepared in situ to avoid oxygen contamination. From the analysis of Ge 3d, Se 3d, and Ag 3d core levels, and valence band spectra, changes in the electronic structure are determined as Ag diffuses gradually with increasing irradiation. The ternary phase based on Ge2Se6 units, which contains homopolar Ge–Ge bonds, forms when diffusion approaches equilibrium where Ag content ∼30 at.%. The formation of a Se-rich composition is indicated in the near-surface region at the initial stage of the process, but the previously assumed Ag2Se phase is not detected.

In Situ Measurements of X-Ray-Induced Silver Diffusion into a Ge30Se70 Thin Film

The surface chemistry of a commercial soda-lime silicate glass is shown to change during a long-duration XPS experiment wherein the glass surface was exposed to the monochromatic x-rays and low-energy electrons (0.2-5 eV) that compensate for the charging of the surface. The atomic percentage of sodium increases and that of oxygen decreases with increasing time of the experiment. The separate influence of x-rays and the low-energy electrons on the glass surface is also measured. The results show that diffusion of the sodium ions is enhanced more in the presence of x-rays than in the presence of low-energy electrons. All observations can be explained well by a model that considers the breaking of the bridging and non-bridging oxygen bonds, and the trapping of photoelectrons and the externally supplied electrons. Although long-duration XPS experiments show significant changes on the exposed surface, the chemical composition of the bulk glass obtained during a short experiment agrees well with that obtained from the chemical analysis.

A. C. Miller

Papers

Role of S /Se ratio in chemical bonding of As-S-Se glasses investigated by Raman, x-ray photoelectron, and extended x-ray absorption fine structure spectroscopies

Structure of Se-rich As-Se glasses by high-resolution x-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy of Al- and B-substituted sodium trisilicate glasses

In Situ Measurements of X-Ray-Induced Silver Diffusion into a Ge30Se70 Thin Film

Surface modification of a silicate glass during XPS experiments