[en] Nondestructive depth profiling method based on reflected electron spectroscopy is presented. Large loss spectra of wide energy range is analyzed. Spectra analysis is performed using two approaches: boundary problem solution using invariant imbedding method and approximate interpretation based on Straight Line Approximation with correction coefficients, which depend on ration of evaporated layer thickness and transport mean free path. It is shown that the transport mean free path, not the inelastic mean free path, limits the information depth of the method in opposite of X-ray photoelectron spectroscopy, elastic peak electron spectroscopy. This fact significantly increase depths that can be analyzed using presented method. Thickness of the evaporated Nb layer on the Si substrate is determined.

[en] The differential inverse inelastic mean free paths (DIIMFP) of beryllium were derived from energy spectra acquired using X-ray photoelectron spectroscopy and electron energy loss spectroscopy techniques by means of the fitting of calculated spectra to experimental data. The calculation of the energy spectra is performed employing the partial intensity approach (PIA). The EELS and XPS spectra were acquired in different laboratories using different Be samples. The comparison of the obtained DIIMFPs with literature data is presented. (paper)

[en] The relative concentration of deuterium implanted into a beryllium sample is determined by elastic peak electron spectroscopy (EPES). The method of partial intensities based on solution of the boundary value problem for the transport equation by the invariant embedding method is used for subsequent determination of the energy spectra of reflected electrons. The differential inverse inelastic mean free paths (DIIMFPs) and the differential surface excitation probability (DSEP) are retrieved using a fitting procedure based on numerous solutions of the direct problem with fitting parameters. The high efficiency of the fitting procedure is based on the technique of numerical solution of equations for the partial intensities, which combines precision and a record-high calculation speed. In the work DIIMFP and DSEP are obtained for both the surface region and for a homogeneous array in the bulk. Calculations of DIIMFP and DSEP are carried out for pure beryllium and for beryllium samples implanted with deuterium. The relative concentrations of deuterium into beryllium were determined at a different fluence. The obtained values of the relative deuterium concentrations are n_D/n_Be = 0.12 ± 0.02 and 0.15 ± 0.03 for an irradiation dose of 5.5 × 10²¹ and 20.1 × 10²¹ m^–2, respectively. The results indicate that, in comparison with the methods used earlier, the developed method allows an order of magnitude in of the sensitivity of determining the relative hydrogen-isotope concentration in compounds to be attained.

[en] The evolution of energy spectra of X-ray photoelectron spectroscopy observed with increasing annealing temperature of graphene oxide (GO) samples is being investigated. The main attention in the work is focused on the region investigation determined by multiple electron energy losses due to π and π + σ plasmon excitations. Such a study allows one to understand an entire structural evolution of GO during thermal reduction process. π plasmon peak becomes prominent only for the samples annealed at the temperatures above 200 °C. Comparison of acquired graphene oxide spectrum (annealed at 1000 °C) with spectrum of highly oriented pyrolytic graphite (HOPG) has been carried out. (paper)

[en] 

Abstract—

Using scanning electron microscopy and X-ray photoelectron spectroscopy, we investigate the chemical forms of tungsten incorporated into diamond-like silicon–carbon films. The films are fabricated by simultaneously carrying out the plasmochemical decomposition of a silicon organic precursor and magnetron sputtering of the metal. Films of tungsten-containing diamond-like silicon–carbon nanocomposites are found to contain a considerable amount of the amorphous phase of tungsten oxide, along with nanocrystalline tungsten carbide.

[en] Elastic peaks electron spectroscopy (EPES) is a perspective tool for measuring the hydrogen atomic density in hydrocarbons. It is known that hydrogen elastic peaks overlap inelastic energy loss spectra. This fact complicates the quantitative interpretation of EPES spectra. In this paper, a novel technique based on the joint use of EPES and X-ray photoelectron spectroscopy (PES) is proposed. A key part of the method is the inelastic scattering background subtraction which is performed in two steps. At the first step, differential inelastic scattering cross-sections are retrieved from PES spectra, while at the second step, the retrieved cross-sections are used to remove the inelastic scattering signal from EPES spectra. Both REELS and PES spectra are described on the base of the invariant imbedding method forming a consistent framework for the surface state analysis. A good agreement is obtained between calculated spectra and experimental data. (paper)

[en] Precise knowledge of the differential inverse inelastic mean free path (DIIMFP) and differential surface excitation probability (DSEP) of Tungsten is essential for many fields of material science. In this paper, a fitting algorithm is applied for extracting DIIMFP and DSEP from X-ray photoelectron spectra and electron energy loss spectra. The algorithm uses the partial intensity approach as a forward model, in which a spectrum is given as a weighted sum of cross-convolved DIIMFPs and DSEPs. The weights are obtained as solutions of the Riccati and Lyapunov equations derived from the invariant imbedding principle. The inversion algorithm utilizes the parametrization of DIIMFPs and DSEPs on the base of a classical Lorentz oscillator. Unknown parameters of the model are found by using the fitting procedure, which minimizes the residual between measured spectra and forward simulations. It is found that the surface layer of Tungsten contains several sublayers with corresponding Langmuir resonances. The thicknesses of these sublayers are proportional to the periods of corresponding Langmuir oscillations, as predicted by the theory of R.H. Ritchie. (paper)

[en] Quantitative analysis of hydrogen isotopes in first wall as well as in construction materials of future fusion devices plays a crucial role to understand the evolution of those materials under operation conditions. A quantitative understanding of hydrogen in materials is also an important issue for storing energy as well as for fuel cells. A combination of Electron Energy Loss Spectroscopy (EELS) and Elastic Peak Electron Spectroscopy (EPES) is presented in this study to tackle these problems of modern material research for energy production and storage. Accurate inelastic scattering background subtraction is a key part of the presented quantitative measurement of the Be/D ratio. The differential inelastic scattering cross-section is determined by the fitting procedure. The fitting procedure is based on the iterative solution of the direct problem and minimization of the residual between computed and measured spectra. This study also takes into account the difference in electron energy loss laws for surface and bulk. The inelastic scattering cross-sections for different doses of deuterium ions in beryllium substrate (5.5·10²¹ m⁻² and 2.01·10²² m⁻²) were defined in a two-layered model. The analysis is carried out for the EELS spectra. Relative concentration of D atoms is defined. (paper)