Simulation of electron spectra for surface analysis (SESSA): a novel software tool for quantitative Auger‐electron spectroscopy and X‐ray photoelectron spectroscopy

Abstract

A description of a new NIST database for quantitative Auger-electron and X-ray photoelectron spectroscopy (AES/XPS) is given: Simulation of Electron Spectra for Surface Analysis (SESSA). This database contains extensive sets of data for the physical quantities relevant to AES and XPS. The internal databases are linked to a user interface via a small expert system that allows a user to automatically retrieve data needed for a specific practical application. SESSA can simulate AES and XPS spectra for a multilayered thin-film sample for measurement conditions specified by the user. Experimental information needed by SESSA is entered via an interface that matches the settings of AES/XPS instrumentation. The structure of SESSA is described together with information on special features, unique capabilities, and sources of the physical data. Examples of practical applications of SESSA for angle-resolved XPS on Al and Si samples, determination of the depth distribution function in XPS, and the use of empirical peak shapes for spectrum simulation are given. These and other applications are contained in SESSA in the form of tutorial files with command-language statements that can be loaded into SESSA and modified as necessary for similar simulations.

Concentration and chemical-state profiles at heterogeneous interfaces with sub-nm accuracy from standing-wave ambient-pressure photoemission

“…The distinction of the peaks from H 2 O(c) and OH À is further justified by examining their different relative intensities through the rocking curve scan (results not shown here). From an analysis of experimental relative core peak intensities using the SESSA XPS simulation program 22,23 the adsorbed water layer is found to be about 5-10 Å thick, although we will later see that the analysis of the SWAPPS results provides a much more accurate value for this thickness of B10 Å. This thickness is significantly larger than that of H 2 O on pure metal oxide surfaces at our relative humidity of B8% (refs 21,24).…”

“…This was done by comparing the relative intensities of all of the peaks shown in Fig. 3a-e, as measured off the Bragg reflection to yield a uniform X-ray flux throughout the sample, with calculated relative intensities from the SESSA XPS simulation program 22,23 . The relevant concentrations in the layer structure of Fig.…”

X-ray photoelectron spectroscopic studies of dolomite surfaces exposed to undersaturated and supersaturated aqueous solutions

“…While this does not change the conclusion that the surface exposed to the supersaturated solution became Ca rich, the Mg enrichment for the sample exposed to the undersaturated solution may be a result of the underestimation of Ca 2p intensity. Quantification of the surface contamination layer thickness and its effects on the detected Ca 2p and Mg 2p signals is possible, but would involve careful calibration of the instrument against all the contamination elements (mainly C and O) and simulations of the XPS spectra (e.g., Smekal et al, 2005). These additional quantitative problems are beyond the scope of this investigation.…”

Electronic structure of delta-doped La:SrTiO3 layers by hard x-ray photoelectron spectroscopy

“…The 0.185 ratio at the energy of our measurements has also been confirmed using more quantitative calculations based on the SESSA program, which includes the effects of elastic scattering, and yields a value of 0.189 very close to it. 17 Broad-range survey spectra collected from both samples are shown in Fig. 1.…”