Much ado about nothing? Background anomalies without accompanying primary peaks in X‐ray photoelectron spectroscopy and low energy Ion scattering

Pinder, Joshua W., Malatinova, Michaela, Kovařík, Martin, Austin, Daniel E., Šikola, Tomáš, Tougaard, Sven, Morgan, David J. ORCID: https://orcid.org/0000-0002-6571-5731, Isaacs, Mark, Průša, Stanislav and Linford, Matthew R. 2025. Much ado about nothing? Background anomalies without accompanying primary peaks in X‐ray photoelectron spectroscopy and low energy Ion scattering. Surface and Interface Analysis 57 (4) , pp. 264-274. 10.1002/sia.7378 Item availability restricted.

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Abstract

X‐ray photoelectron spectroscopy (XPS) and low energy ion scattering (LEIS) are important methods for identifying and quantifying the elements at surfaces. XPS largely deals with zero‐loss peaks produced by unattenuated photoemission, and the focus of LEIS is similarly surface peaks resulting from direct scattering from surface atoms. However, the backgrounds of these spectra also contain information. They can help reveal the structures and distributions of the atoms and layers at surfaces. Here, we show abnormalities in XPS and LEIS backgrounds that are not accompanied by zero‐loss photoemission or surface peaks. These features are due to buried atoms that are far enough from the surface that they cannot produce zero loss or surface peaks but close enough to affect spectral backgrounds. This Insight Note was written to alert the reader to the existence and usefulness of these backgrounds. Spectra with background abnormalities were poorly modeled by multiple linear regression, that is, as linear combinations of the pure‐material spectra. However, XPS backgrounds with anomalies can be well modeled using the QUASES software, even when zero‐loss peaks are not apparent. With QUASES, it is also possible to correct the substrate spectrum for distortions caused by inelastic electron scattering. When unusual baseline features appear in XPS or LEIS spectra, it can be helpful to use a complementary technique that probes at a greater depth to confirm the presence and identity of the atoms causing the anomaly. The effects in this work were demonstrated via a lighter coating of SiO2 on a heavier stainless‐steel substrate.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Chemistry Research Institutes & Centres > Cardiff Catalysis Institute (CCI)
Publisher:	Wiley
ISSN:	0142-2421
Funders:	Restek
Date of First Compliant Deposit:	10 February 2025
Date of Acceptance:	23 December 2024
Last Modified:	17 Mar 2025 11:30
URI:	https://orca.cardiff.ac.uk/id/eprint/175988

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