Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 43: Clean surfaces III
O 43.2: Talk
Wednesday, March 28, 2012, 10:45–11:00, MA 043
Ultrathin zirconia films on Pt3Zr — Moritz Antlanger, Jiří Pavelec, Peter Varga, Ulrike Diebold, and •Michael Schmid — TU Wien, Austria
Zirconium dioxide (ZrO2) has numerous applications, from high-performance ceramics for engineering and dentistry to gas sensors and solid-oxide fuel cells (SOFC). Its performance in sensors and SOFCs is based on its high bandgap (≈ 6 eV), which implies a low electronic conductivity even at high temperatures where it becomes an ionic conductor. This excludes many charged-particle techniques such as scanning tunneling microscopy (STM) for the study of bulk ZrO2. We have therefore produced ultrathin zirconia films by oxidation of a Pt3Zr alloy single crystal and determined their surface structure and properties by STM. The ultrathin film consists of a single O-Zr-O trilayer, exhibits a bandgap, and is remarkably stable. The interface structure between the ultrathin oxide and the substrate is analyzed from STM measurements and shows a reconstructed Pt layer. The surface is oxygen-terminated and almost defect-free, yet the surface diffusivity of Pd on the ZrO2 film is much lower than on oxygen-terminated alumina surfaces.
This work was supported by the Austrian Science Fund (FWF; project F45).