323,089 research outputs found
Data for: Method to correct ambient pressure XPS for the distortion caused by the gas
No full textCross Section for N2 gas published as figure 2 in Sven Tougaard and Mark Greiner,"Method to correct ambient pressure XPS for the distortion caused by the gas"Applied Surface Science. (2020)First column: energy loss T in eVSecond column: the cross section K(T) in the form: IMFP*K(T) in units (1/eV) where IMFP is the inelastic mean free path and K(T)dT is the probability for the electron to lose energy in the interval T to T+ dT per unit path length travelled in the gas. It can be used with the QUASES software to correct XPS taken in a N2 gas for the distortions caused by the gas. IMFP*K(T) is the form used as input in the software
QUEELS-XPS: Software to calculate the energy loss processes in XPS and AES including the effects of the core hole.
No full textXPS spectra consist of the primary photo-excited core electrons, including processes such as lifetime broadening, spin-orbit coupling, and multiplet splitting. On top of this, there is a background of energy-loss structures caused by excitations due to the sudden creation of the static core hole and due to electron transport out of the surface (including bulk and surface effects). The corresponding energy-loss processes are usually denoted ‘‘intrinsic’’ and ‘‘extrinsic’’ excitations. The QUEELS-XPS software calculates these effects quantitatively by a dielectric response description. It also applies to AES. The only input in the software is the dielectric function expressed by the energy loss function (ELF). The ELF for various materials is available at:
Pauly, Nicolas, Yubero, Francisco, & Tougaard, Sven. (2022). ELF dielectric functions for various materials. (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.6024064
The QUEELS-XPS software was first presented in the paper
Software package to calculate the effects of the core hole and surface excitations on XPS and AES
S. Tougaard and F. Yubero, Surface Interface Analysis 44, 1114-1118 (2012)
Note: The QUEELS-XPS software will be available here soon and can presently be downloaded at http://quases.com/products/queels-xps/
The QUEELS-XPS software is an extension of the QUEELS software which applies to EELS, REELS, AES, and XPS. QUEELS is presented in the paper "QUEELS: Software to calculate the energy loss processes in TEELS, REELS, XPS and AES including effects of the core hole"; by S. Tougaard, N. Pauly, F. Yubero, Surf. Interf Anal (2022) http://doi.org/10.1002/sia.7095. The QUEELS software can be downloaded here:
Tougaard, Sven, & Yubero, Francisco. (2022). QUEELS software for calculation of energy loss processes in TEELS, REELS, XPS, and AES including effects of the core hole (2.3). Zenodo. https://doi.org/10.5281/zenodo.6022426
Recent applications of QUEELS-XPS:
XPS primary excitation spectra of Zn 2p, Fe 2p, and Ce 3d from ZnO, α-Fe2O3, and CeO2
N. Pauly, F. Yubero, J.P. Espinós, S. Tougaard. Surface and Interface Analysis 51, 353-360 (2019) https://doi.org/10.1002/sia.6587
Quantitative analysis of Yb 4d photoelectron spectrum of metallic Yb
N. Pauly, F. Yubero, S. Tougaard, Surface and Interface Analysis 50, 1168-1173 (2018); https://doi.org/10.1002/sia.6402
Quantitative analysis of satellite structures in XPS spectra of gold and silver
N. Pauly, F. Yubero, S. Tougaard, Applied Surface Science 383, 317–323 (2016); http://dx.doi.org/10.1016/j.apsusc.2016.03.185
Quantitative analysis of Ni 2p photoemission in NiO and Ni diluted in a SiO2 matrix
N. Pauly, F. Yubero, F.J. García-García, S. Tougaard, Surf. Sci. 644, 46-52 (2016) http://dx.doi.org/10.1016/j.susc.2015.09.012
LMM Auger primary excitation spectra of copper
N. Pauly, S. Tougaard, F. Yubero, Surface Science 630, 294–299 (2014) http://dx.doi.org/10.1016/j.susc.2014.08.029
Modeling of X-ray photoelectron spectra: surface and core hole effects
N. Pauly, F. Yubero, S. Tougaard, Surface and Interface Analysis 46, 920-923 (2014) ; http://dx.doi.org/10.1002/sia.5372
Determination of the Cu 2p primary excitation spectra for Cu, Cu2O and CuO
N. Pauly, S. Tougaard, F. Yubero, Surface Science 620, 17-22 (2014); http://dx.doi.org/10.1016/j.susc.2013.10.009
Dielectric description of the angular dependence of the loss structure in core level photoemission
F. Yubero and S. Tougaard, J. Electron Spectroscopy and Related Phenomena 185 (2012) 552-5
Differential energy loss probability for 1000 eV electrons in N2 gas.
No full textDifferential Cross section for 1000 eV electrons in N2 gas determined in the paper:
"Method to correct ambient pressure XPS for the distortion caused by the gas"
by
SvenTougaard and Mark Greiner
published in Applied Surface Science 2020:
https://doi.org/10.1016/j.apsusc.2020.147243
Data structure:
Energy loss T (eV), IMFP*K(T) (eV^-1)
(where IMFP is the inelastic mean free path
QUASES-Inelastic electron mean free path calculator (by TPP2M formula)
No full textThe QUASES-IMFP-TPP2M-CF software is a user friendly calculator for the inelastic electron mean free path for electrons in materials. It is based on the Tanuma, Powell and Penn algorithm [1] and has an option to account for relativistic effects [2].
The software includes a database with parameter values for all elements and a wide range of compounds, oxides, and polymers. There are also facilities to easily expand the database with new materials.
The software also provides means to calculate the elastic scattering correction in XPS. The change in XPS peak intensity from a layer of atoms at depth z, caused by elastic electron scattering, is conveniently described by a correction factor CF, which can be estimated with the software within two approximations [3,4,5]. For a practical application watch videos 6, 8 and 9 at: https://doi.org/10.5281/zenodo.5499741.
A manual is integrated in the software.
[1] S. Tanuma, C. J. Powell, D. R. Penn:Surf. Interf. Anal. 21(1994)165
[2] H. Shinotsuka, S. Tanuma, C. J. Powell, D. R. Penn: Surf. Interf. Anal. 47(2015)871
[3] A.Jablonski, S.Tougaard, 'Practical Correction Formula for Elastic Electron Scattering Effects in Attenuation of Auger and Photoelectrons',Surf. Interf. Anal. 26(1998)17
[4] Jablonski, S.Tougaard, Surf. Interf. Anal. 26(1998)374
[5] S. Tougaard, Practical guide to the use of backgrounds in quantitative XPS, J. Vac. Sci. Technol. A 39, 011201 (2021); https://doi.org/10.1116/6.0000661
Copyright (c) 2000-2022 All rights reserved
The software code is written by Sven Tougaard.
Copyright (c) 2000-2021 Quases-Tougaard Inc.
Free to use for non-commercial applications.
Sven Tougaard, Dept of Physics, Chemistry, and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmar
QUEELS software for calculation of energy loss processes in TEELS, REELS, XPS, and AES including effects of the core hole
No full textQUEELS is for calculation of energy loss processes in TEELS, REELS, XPS, and AES including effects of the core hole
It is based on a dielectric response description of the interaction of the moving electron with the electrons of the solid and includes the boundary effects imposed by the particular experimental situation. Its validity has been verified in several experiments.
The QUEELS software can be downloaded at: doi: 10.5281/zenodo.6022426
QUEELS is free to use for non-commercial applications.
The software is based on theory published in the papers:
1. J. Lindhard, Kgl Danske Vid Selsk Mat-Fys Medd 28:8 (1954)
2. R H. Ritchie, Phys. Rev. 106, p. 874 (1957)
3. F. Yubero and S. Tougaard, Phys. Rev. B46, p. 2486, (1992)
4. F. Yubero, JM Sanz, B. Ramskov, S. Tougaard, Phys. Rev. B53, p. 9719,(1996)
5. AC. Simonsen, F. Yubero, S. Tougaard, Phys. Rev. B56, p. 1612, (1997)
A brief summary of the theory behind QUEELS and discussion of its practical application is published in the paper which can be downloaded here: :https://doi-org.proxy1-bib.sdu.dk/10.1002/sia.7095.
S. Tougaard, N. Pauly, F. Yubero, QUEELS: Software to calculate the energy loss processes in TEELS, REELS, XPS, and AES including effects of the core hole, Surf. Interf. Anal. 54, p. 820-833 (2022).
A brief users guide is available in the supplementary material to this paper.
The only input needed in QUEELS is the dielectric function of the material expressed by the so called energy loss function (ELF) as a sum of oscillators.
You may get acquainted with the software by reproducing the spectra shown in the guide and the abovementioned paper for Au and Si.
To do this, you first copy the files ELF_Au.txt and ELF_Si.txt into a folder e.g. C:\ELF\ELF_Au.txt. Then read the file with the "Set Material Parameters" menu in QUEELS.
ELF for a range of other materials can be found in:
Pauly, Nicolas, Yubero, Francisco, & Tougaard, Sven. (2022). ELF dielectric functions for various materials. (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.6024064
Copyright (c) 2001-2022 All rights reserved
QUEELS software is developed by Sven Tougaard and Francisco Yubero
Sven Tougaard, Dept of Physics, Chemistry, and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark
Francisco Yubero, Inst. de Ciencia de Materiales de Sevilla, Isla de la Cartuja, E-41092 Sevilla, Spain
(e-mails: [email protected] and [email protected]
Tutorial videos on the application of XPS inelastic background for characterization of composition and morphology of nano-structures with QUASES software
No full textThe tutorial videos illustrate the application of XPS inelastic background analysis for characterization of composition and morphology of nano-structures with QUASES software.
For an introduction to the method, see:
S. Tougaard "Practical guide to the use of backgrounds in quantitative XPS." J Vac Sci Technol A. 2021;39:011201. doi:10.1116/6.0000661
S. Tougaard "Accuracy of the non-destructive surface nanostructure quantification technique based on analysis of the XPS or AES peak shape". Surf Interface Anal. 1998;26(4):249-269. doi:https://doi-org.proxy1-bib.sdu.dk/10.1002/(SICI)1096-9918(199804)26:43.0.CO;2-A
The inelastic background analysis was done with the QUASES-Tougaard software . See www. quases.com.
It is recommended to read first the short description in the pdf file: Guide to the 14 posted videos.pdf. This explains briefly the purpose of each video.
To best understand what is done in Video 9 ("9.Practical procedure to correct for elastic electron scattering.mp4") you should first watch Video 8, then Video 6 and then Video 9
Determining nonuniformities of core‐shell nanoparticle coatings by analysis of the inelastic background of X‐ray photoelectron spectroscopy survey spectra
Full text linkMost real core‐shell nanoparticle (CSNP) samples deviate from an ideal core‐shell structure potentially having significant impact on the particle properties. An ideal structure displays a spherical core fully encapsulated by a shell of homogeneous thickness, and all particles in the sample exhibit the same shell thickness. Therefore, analytical techniques are required that can identify and characterize such deviations. This study demonstrates that by analysis of the inelastic background in X‐ray photoelectron spectroscopy (XPS) survey spectra, the following types of deviations can be identified and quantified: the nonuniformity of the shell thickness within a nanoparticle sample and the incomplete encapsulation of the cores by the shell material. Furthermore, CSNP shell thicknesses and relative coverages can be obtained. These results allow for a quick and straightforward comparison between several batches of a specific CSNP, different coating approaches, and so forth. The presented XPS methodology requires a submonolayer distribution of CSNPs on a substrate. Poly(tetrafluoroethylene)‐poly(methyl methacrylate) and poly(tetrafluoroethylene)‐polystyrene polymer CSNPs serve as model systems to demonstrate the applicability of the approach.Peer Reviewe
XPS quantification with universal inelastic electron scattering cross section including intrinsic excitations
Full text linkIn X-ray excited photoelectron emission (XPS), the shape and intensity of photoelectron peaks are strongly affected by extrinsic excitations due to electron transport out of the surface. It is also influenced by intrinsic excitations due to the sudden creation of the static core hole. In order to approximately determine the primary excitation spectrum of the considered transition corrected for both extrinsic and intrinsic excitations, we developed in a previous work [E. Gnacadja, N. Pauly, S. Tougaard, Surf. Interface Anal. 52 (2020) 413] a universal analytical expression for the energy loss cross section including extrinsic and intrinsic excitations. We apply the present universal cross section to test to what extent these primary excitations spectra can be used for XPS quantification based on peak area ratios. The procedure is applied to the study of three sets of polycrystalline alloys (Cu0.75Au0.25, Cu0.50Au0.50, and Cu0.25Au0.75) and to three metal oxides (HfO2, ZrO2, and Cu2O). We show that although the individual peaks are very different from those obtained with the classical universal Tougaard cross section, the determined quantitative compositions are equivalent (but not better). This implies that the relative contribution from intrinsic excitations is roughly the same for all peaks for a given sample and they therefore cancel out when peak area ratios are considered.</p
Three-Dimensional X-Ray Photoelectron Tomography on the Nanoscale: Limits of Data Processing by Principal Component Analysis
Full text linkIn a previous article, we studied the influence of spectral noise on a new method for three-dimensional X-ray photoelectron spectroscopy (3D XPS) imaging, which is based on analysis of the XPS peak shape [Hajati, S., Tougaard, S., Walton, J. & Fairley, N. (2008). Surf Sci 602, 3064-3070]. Here, we study in more detail the influence of noise reduction by principal component analysis (PCA) on 3D XPS images of carbon contamination of a patterned oxidized silicon sample and on 3D XPS images of Ag covered by a nanoscale patterned octadiene layer. PCA is very efficient for noise reduction, and using only the three most significant PCA factors to reconstruct the spectra restores essentially all physical information in both the intensity and shape of the XPS spectra. The corresponding signal-to-noise improvement was estimated to be equivalent to a reduction by a factor of 200 in the required data acquisition time. A small additional amount of information is obtained by using up to five PCA factors, but due to the increased noise level, this information can only be extracted if the intensity of the start and end points for each spectrum are obtained as averages over several energy points
Data for: Method to correct ambient pressure XPS for the distortion caused by the gas
No full textCross Section for N2 gas published as figure 2 in Sven Tougaard and Mark Greiner,"Method to correct ambient pressure XPS for the distortion caused by the gas"Applied Surface Science. (2020)First column: energy loss T in eVSecond column: the cross section K(T) in the form: IMFP*K(T) in units (1/eV) where IMFP is the inelastic mean free path and K(T)dT is the probability for the electron to lose energy in the interval T to T+ dT per unit path length travelled in the gas. It can be used with the QUASES software to correct XPS taken in a N2 gas for the distortions caused by the gas. IMFP*K(T) is the form used as input in the software.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
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