Generalized molybdenum oxide surface chemical state XPS determination via informed amorphous sample model

• Published in: Applied surface science Vol. 326; pp. 151 - 161
• Main Authors: Baltrusaitis, Jonas, Mendoza-Sanchez, Beatriz, Fernandez, Vincent, Veenstra, Rick, Dukstiene, Nijole, Roberts, Adam, Fairley, Neal
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.01.2015; Elsevier
• Subjects: Condensed Matter; Fittings; Informed amorphous sample model; Materials Science; Molybdenum oxide; Molybdenum oxides; Physics; Semiconductors; Spectra; Spectra envelope; Valence; X-ray photoelectron spectrometry; X-ray photoelectron spectroscopy; X-rays; X-ray photoelectron spectrometry; Informed amorphous sample model; Molybdenum oxide; Spectra envelope
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.11.077

•We analyzed and modeled spectral envelopes of complex molybdenum oxides.•Molybdenum oxide films of varying valence and crystallinity were synthesized.•MoO3 and MoO2 line shapes from experimental data were created.•Informed amorphous sample model (IASM) developed.•Amorphous molybdenum oxide XPS envelopes were interpreted. Accurate elemental oxidation state determination for the outer surface of a complex material is of crucial importance in many science and engineering disciplines, including chemistry, fundamental and applied surface science, catalysis, semiconductors and many others. X-ray photoelectron spectroscopy (XPS) is the primary tool used for this purpose. The spectral data obtained, however, is often very complex and can be subject to incorrect interpretation. Unlike traditional XPS spectra fitting procedures using purely synthetic spectral components, here we develop and present an XPS data processing method based on vector analysis that allows creating XPS spectral components by incorporating key information, obtained experimentally. XPS spectral data, obtained from series of molybdenum oxide samples with varying oxidation states and degree of crystallinity, were processed using this method and the corresponding oxidation states present, as well as their relative distribution was elucidated. It was shown that monitoring the evolution of the chemistry and crystal structure of a molybdenum oxide sample due to an invasive X-ray probe could be used to infer solutions to complex spectral envelopes.