Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 28: Thin film characterization: structure analysis and composition (Spectroscopy)
DS 28.5: Vortrag
Mittwoch, 28. März 2012, 18:45–19:00, H 2032
Chemical Depth Profiles of Ternary Pd Alloys by HAXPES and First Spectra Simulations — •Julius Kühn1,3, Andreas Lippitz1, Thomas Gross1, Mihaela Gorgoi2, Sebastian Linke3, Werner Moritz3, and Wolfgang Unger1 — 1BAM Federal Institue of Materials Research and Testing, Berlin, Germany — 2Helmholtz Zentrum Berlin, BESSY II, Berlin, Germany — 3Department of Physical Chemistry, Humboldt-Universität zu Berlin, Germany
The catalytic activity of Pd is well known. By alloying with other transition metal the resistivity against poisoning due to sulfur can be improved. In our study we investigated the chemical states of a PdNiCo ternary thin film alloy used as the catalytically active layer in a hydrogen sensor by hard X-ray photo electron spectroscopy (HAXPES). The new technique offers the possibility to study the first nanometers of the sample by increasing the excitation energy from 2010 eV to 6000 eV to perform a non-destructive chemical state depth profiling across the surface of the alloy layer down to 18 nm. We studied the influence of hydrogen and hydrogen sulfide exposure and temperature treatments on the chemical composition of the alloy surface. In addition hard XP-spectra of PdNiCo alloys were calculated by the Simulation of Electron Spectra for Surface Analysis (SESSA) software and compared to experimental data. By doing this evidence for segregation phenomena at the ternary alloy surface is derived.