Ga. Carson et al., EPITAXIAL-GROWTH OF CO3O4 ON COO(100), Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 14(3), 1996, pp. 1637-1642
Citations number
34
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
Under mildly oxidizing ultrahigh vacuum conditions, it is possible to
form on top of CoO(100) single crystal substrates, thin films that hav
e higher oxygen content but that preserve the overall symmetry of the
CoO(100) low-energy electron diffraction pattern. X-ray photoelectron
spectroscopy (XPS) and high-resolution electron-energy-loss spectrosco
py (HREELS) data indicate that the epitaxial film grown on CoO(100) at
625 K and 5x10(-7) Torr is Co3O4-like in both oxygen content and XP/H
REEL spectroscopic characteristics. Both materials are closest packed
in lattice oxygen, with the mismatch of bulk O2--O2- distances of appr
oximately 5%. However, the Co3O4 is only able to grow to a thickness o
f approximately 5 Angstrom before the oxidation process halts. It is p
roposed that the orientation of Co3O4 that forms most readily on the C
oO(100) surface does not present a thermodynamically stable orientatio
n of the bulk Co3O4 substrate but is that which grows under the constr
aint of the best CoO(100)/Co3O4 epitaxial arrangement. While the misma
tch in lattice parameters may in part be to blame for the limitation o
f higher oxide thickness, thicker oxide films have been grown under co
nditions with significantly larger mismatch. (C) 1996 American Vacuum
Society.