Control of the stoichiometry in the deposition of cobalt oxides on SiO2

✍ Scribed by Jiménez, V. M.; Espinós, J. P.; González-Elipe, A. R.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 334 KB
• Volume: 26
• Category: Article
• ISSN: 0142-2421
• DOI: 10.1002/(sici)1096-9918(199801)26:1<62::aid-sia349>3.0.co;2-r

✦ Synopsis

Both CoO and overlayers have been deposited on by evaporation from metallic Co and subsequent Co 3 O 4 SiO 2 oxidation with oxygen and a plasma of oxygen. The combined use of ion scattering spectroscopy and XPS shows that both oxides grow in the form of small particles on the surface of Ion scattering spectroscopy also shows SiO 2 . that the surface of cobalt oxide exposed to a plasma of oxygen is enriched in oxygen ions with respect to the surface of the cobalt oxide formed by exposure to oxygen. The Co 2p spectra corresponding to the deposits obtained by oxidation with are characteristic of CoO, while those corresponding to the deposits obtained after O 2 oxidation with a plasma are typical of Moreover, the ratios determined by XPS and factor Co 3 O 4 . O Co /Co analysis indicate the formation of CoO stoichiometry in the former case and stoichiometry in the latter. It Co 3

O 4 has also been observed that no shift in either binding energy or modiÐed Auger parameter aº appears as a function of coverage. This absence of shifts is interpreted as a consequence of the type of screening mechanism that dominates the relaxation of the photoholes in these oxides.