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Study of the early stages of growth of Co oxides on oxide substrates
Author(s) -
DíazFernández D.,
Méndez J.,
Yubero F.,
DomínguezCañizares G.,
Gutiérrez A.,
Soriano L.
Publication year - 2014
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.5366
Subject(s) - x ray photoelectron spectroscopy , oxide , spinel , cobalt , evaporation , metal , monolayer , cobalt oxide , layer (electronics) , chemical engineering , oxygen , materials science , chemistry , analytical chemistry (journal) , inorganic chemistry , nanotechnology , metallurgy , physics , organic chemistry , chromatography , engineering , thermodynamics
The growth of Cobalt oxides by reactive thermal evaporation of metallic Cobalt in an oxygen atmosphere on a series of oxide substrates, namely SiO 2 , Al 2 O 3 and MgO, has been chemically and morphologically studied by means of XPS and atomic force microscopy (AFM). The XPS results reveal that cobalt oxide grows as CoO (Co 2+ ) for coverages up to some tens of equivalent monolayers on all substrates. For larger coverages, the formation of the spinel oxide Co 3 O 4 has been observed. AFM and XPS quantification allowed us to determine the way of growth of CoO on all substrates, being of Volmer–Weber (i.e. islands) mode for SiO 2 , whereas for Al 2 O 3 and MgO, the growth follows the Frank‐van der Merwe (i.e. layer‐by‐layer) mode. The results are discussed in terms of the mismatch of the lattice parameters of the CoO adsorbates with the substrates. Copyright © 2014 John Wiley & Sons, Ltd.