title: Depth-Resolved X-ray Absorption Spectroscopy by Means of Grazing Emission X-ray Fluorescence.
abstract: 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.
authors.affiliation: Paul Scherrer Institut , 5232 Villigen-PSI, Switzerland.
authors.forename: Yves
authors.initials: Y
authors.lastname: Kayser
authors.affiliation: University of Uppsala , Ångström Laboratory, Department of Chemistry, 751 05 Uppsala, Sweden.|Polish Academy of Sciences , Institute of Physical Chemistry, 01-224 Warsaw, Poland.
authors.forename: Jacinto
authors.initials: J
authors.lastname: Sá
authors.affiliation: Paul Scherrer Institut , 5232 Villigen-PSI, Switzerland.|Jan Kochanowski University , Institute of Physics, 25-406 Kielce, Poland.
authors.forename: Jakub
authors.initials: J
authors.lastname: Szlachetko