Few-monolayer yttria-doped zirconia films: Segregation and phase stabilization
Peter Lackner1, Amy J Brandt1, Ulrike Diebold1
1Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
The Journal of Chemical Physics
|February 17, 2020
Summary
Yttria-doped zirconia films stabilize the tetragonal phase at low dopant concentrations. This study reveals yttria segregation to the surface, crucial for understanding zirconia surface properties.
Area of Science:
- Materials Science
- Surface Science
- Catalysis
Background:
- Zirconia (ZrO2) is commonly doped with yttria for enhanced oxygen ion conductivity.
- Previous surface studies were limited by impurities, hindering accurate phase analysis.
Purpose of the Study:
- To investigate the surface properties of yttria-doped zirconia films on Rh(111).
- To determine the effect of low yttria concentrations on zirconia phase stabilization.
- To analyze yttria segregation behavior on the zirconia surface.
Main Methods:
- X-ray photoelectron spectroscopy (XPS) for chemical state analysis.
- Scanning tunneling microscopy (STM) for surface morphology.
- Low-energy electron diffraction (LEED) for structural analysis.
Main Results:
- Tetragonal phase stabilization observed at unexpectedly low dopant concentrations (0.5 mol % Y2O3).
- Yttria segregation to the surface confirmed by XPS.
- Estimated segregation enthalpy of -23 ± 4 kJ/mol for yttria.
Conclusions:
- Low yttria doping effectively stabilizes the tetragonal phase of zirconia films.
- Yttria surface segregation is a significant factor in the surface chemistry of doped zirconia.
- Findings provide insights into the surface behavior of yttria-doped zirconia for applications.
