Abstract
A detailed picture of the thermally activated processes occurring at the Co/ZnO interface is obtained by a combination of high energy X-ray based techniques: X-ray photoelectron and absorption spectroscopies and the kinematical X-ray standing wave method. At room temperature, the growth of a few monolayers of cobalt proceeds by the nucleation of nanometer-sized clusters on the polar oxygen-terminated (0001̄) surface of a ZnO single crystal. Progressive annealing from 600 to 970 K allows separating the various interfacial reactions. At the lowest annealing temperature, Co clusters coalesce while keeping their metallic character. Above 700 K Co is gradually oxidized to Co and a thin Co rich (Zn,Co)O layer is formed. It is observed that rock salt CoO phases may form at the surface when the initial Co thickness exceeds 1 nm. At the highest annealing temperature (970 K), Co diffuses deeper into ZnO and Zn vacancies are created at subsurface sites that were previously occupied by Co.
Original language | English |
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Pages (from-to) | 7411-7418 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry C: Nanomaterials and interfaces |
Volume | 115 |
Issue number | 15 |
DOIs | |
Publication status | Published - 21 Apr 2011 |
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Synthesis, Irradiation and Analysis of Materials (SIAM)
Louette, P. (Manager), Colaux, J. (Manager), Felten, A. (Manager), Tabarrant, T. (Operator), COME, F. (Operator) & Debarsy, P.-L. (Manager)
Technological Platform Synthesis, Irradiation and Analysis of MaterialsFacility/equipment: Technological Platform