Spontaneous dissociation of Co2(CO)8 and autocatalytic growth of Co on SiO2: A combined experimental and theoretical investigation
We present experimental results and theoretical simulations of the adsorption behavior of the metal–organic precursor Co2(CO)8 on SiO2 surfaces after application of two different pretreatment steps, namely by air plasma cleaning or a focused electron beam pre-irradiation. We observe a spontaneous dissociation of the precursor molecules as well as autodeposition of cobalt on the pretreated SiO2 surfaces. We also find that the differences in metal content and relative stability of these deposits depend on the pretreatment conditions of the substrate. Transport measurements of these deposits are also presented. We are led to assume that the degree of passivation of the SiO2 surface by hydroxyl groups is an important controlling factor in the dissociation process. Our calculations of various slab settings, using dispersion-corrected density functional theory, support this assumption. We observe physisorption of the precursor molecule on a fully hydroxylated SiO2 surface (untreated surface) and chemisorption on a partially hydroxylated SiO2 surface (pretreated surface) with a spontaneous dissociation of the precursor molecule. In view of these calculations, we discuss the origin of this dissociation and the subsequent autocatalysis.
|Author:||Kaliappan Muthukumar, Harald O. Jeschke, Roser Valentí, Evgeniya Begun, Johannes Schwenk, Fabrizio Porrati, Michael Huth|
|Parent Title (English):||Beilstein journal of nanotechnology|
|Publisher:||Beilstein-Institut zur Förderung der Chemischen Wissenschaften|
|Place of publication:||Frankfurt, M.|
|Date of Publication (online):||25.07.2012|
|Date of first Publication:||25.07.2012|
|Publishing Institution:||Univ.-Bibliothek Frankfurt am Main|
|Tag:||Co2(CO)8; EBID; FEBID; deposition; dissociation; precursor; radiation-induced nanostructures|
|Dewey Decimal Classification:||530 Physik|
|620 Ingenieurwissenschaften und zugeordnete Tätigkeitenn|
This is an Open Access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
|Licence (German):||Creative Commons - Namensnennung 2.0|