Regensburg 2016 – scientific programme
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DS: Fachverband Dünne Schichten
DS 35: Thin Film Characterisation: Structure Analysis and Composition II
DS 35.2: Talk
Wednesday, March 9, 2016, 15:15–15:30, H8
Electronic properties of LaPO4 nanoparticles studied by thehard X-Ray photoelectron spectroscopy. — •A. Gloskovskii1, Ya. Chornodolskyy2, V. Vistovskyy2, O. Shevchuk3, O. Myagkota3, S. Syrotyuk3, A. Zaichenko3, A. Voloshinovskii2, and W. Drube1 — 1Photon Science/DESY, Hamburg — 2Ivan Franko National University of Lviv, Ukraine — 3Lviv Polytechnic National University, Ukraine
Photoelectron spectroscopy using excitation by hard X-rays in the range of 2 - 15 eV (HAXPES) is rapidly developing at synchrotron light sources worldwide. Its comparatively large probing depth (10-30 nm) makes it a powerful tool for studies of complex materials, buried nanostructures and multilayered structures relevant for device applications. We are presenting a new approach for HAXPES of insulating nanoparticles by covering them with thin metal shell. It makes it feasible to probe density of occupied states (DOS) for insulating nanoparticles. LaPO4-Eu nanoparticles with mean grain size of 50-60 nm were covered by 1 nm Ag resulting in core-shell particles. DOS of conductive silver shell is not overlapping with DOS of wide bandgap LaPO4. We carried out HAXPES measurements with variable linear light polarizations using 5.95 keV photons. The intensity of s-states can be considerably suppressed by rotating the light polarization perpendicularly to the analyzer’s axis. In this way the extraction of the s- and p- contributions to LaPO4 valence band becomes feasible. Experimentally measured valence band DOS correlates well with calculations using projector augemented wave method.