Understanding the effects of sputter damage in W–S thin films by HAXPES
2014 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 305, 203-213 p.Article in journal (Refereed) Published
WS2 is an excellent solid lubricant in dry conditions, and can be applied as thin films. The analysis of WS2 and WS2-based films by x-ray photoelectron spectroscopy (XPS) can be challenging, due to contaminationand oxidized material on the surface. The investigations have traditionally therefore included sputter etching by ion bombardment, which however leads to changes of the remaining material. In this study, hard x-ray photoelectron spectroscopy (HAXPES) has been used to study W–S films deposited bymagnetron sputtering. High-resolution reference measurements for crystalline WS2 and metallic W are also presented. The W–S films were analyzed before and after sputter cleaning by Ar+ ion bombardment, using photon energies of 3 and 6 keV. The as-deposited films were found to consist mainly of a WSx phase,similar to WS2 but with a broader range of chemical states. It is shown that ion bombardment of the surface not only removes the outermost oxidized material, but also leads to preferential sputtering of sulfur and the formation of metallic tungsten. The results are of strong interest for the analysis of WS2-based materials, as they demonstrate that spectra from sputter-cleaned films include effects of sputter damage,and may not be representative of the original sample.
Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 305, 203-213 p.
Inorganic Chemistry Materials Chemistry Condensed Matter Physics
Research subject Chemistry with specialization in Inorganic Chemistry; Physics with spec. in Atomic, Molecular and Condensed Matter Physics
IdentifiersURN: urn:nbn:se:uu:diva-224513DOI: 10.1016/j.apsusc.2014.03.038ISI: 000336525400028OAI: oai:DiVA.org:uu-224513DiVA: diva2:716971
FunderSwedish Foundation for Strategic Research