Few-monolayer yttria-doped zirconia films: Segregation and phase stabilization

Peter Lackner; Amy J Brandt; Ulrike Diebold; Michael Schmid

doi:10.1063/1.5140266

Few-monolayer yttria-doped zirconia films: Segregation and phase stabilization

J Chem Phys. 2020 Feb 14;152(6):064709. doi: 10.1063/1.5140266.

Authors

Peter Lackner¹, Amy J Brandt¹, Ulrike Diebold¹, Michael Schmid¹

Affiliation

¹ Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.

PMID: 32061213
DOI: 10.1063/1.5140266

Abstract

For most applications, zirconia (ZrO₂) is doped with yttria. Doping leads to the stabilization of the tetragonal or cubic phase and increased oxygen ion conductivity. Most previous surface studies of yttria-doped zirconia were plagued by impurities, however. We have studied doping of pure, 5-monolayer ZrO₂ films on Rh(111) by x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and low-energy electron diffraction (LEED). STM and LEED show that the tetragonal phase is stabilized by unexpectedly low dopant concentrations, 0.5 mol % Y₂O₃, even when the films are essentially fully oxidized (as evidenced by XPS core level shifts). XPS also shows Y segregation to the surface with an estimated segregation enthalpy of -23 ± 4 kJ/mol.