Depth-Resolved X-ray Absorption Spectroscopy by Means of Grazing Emission X-ray Fluorescence
2015 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 87, no 21, 10815-10821 p.Article in journal (Refereed) Published
Grazing emission X-ray fluorescence (GEXRF) is well suited for nondestructive elemental-sensitive depth-profiling measurements on samples with nanometer-sized features. By varying the grazing emission angle under which the X-ray fluorescence signal is detected, the probed depth range can be tuned from a few to several hundred nanometers. The dependence of the XRF intensity on the grazing emission angle can be assessed in a sequence of measurements or in a scanning-free approach using a position-sensitive area detector. Hereafter, we will show that the combination of scanning-free GEXRF and fluorescence detected X-ray absorption spectroscopy (XAS) allows for depth-resolved chemical speciation measurements with nanometer-scale accuracy. While the conventional grazing emission geometry is advantageous to minimize self-absorption effects, the use of a scanning-free setup makes the sequential scanning of the grazing emission angles obsolete and paves the way toward time-resolved depth-sensitive XAS measurements. The presented experimental approach was applied to study the surface oxidation of an Fe layer on the top of bulk Si and of a Ge bulk sample. Thanks to the penetrating properties and the insensitivity toward the electric conduction properties of the incident and emitted X-rays, the presented experimental approach is well suited for in situ sample surface studies in the nanometer regime.
Place, publisher, year, edition, pages
2015. Vol. 87, no 21, 10815-10821 p.
Physical Chemistry Analytical Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-268407DOI: 10.1021/acs.analchem.5b03346ISI: 000364354900026PubMedID: 26458105OAI: oai:DiVA.org:uu-268407DiVA: diva2:878475