Experimental Determination of the Electronic Structure of Small Metal Particles.
Abstract
Low electronegativity metals such as Sm, Cs, and Na have been examined in the search for metal with strong catalytic activity in promoting the oxidation of semiconductor surfaces. A preliminary study shows that Sm overlayers appear to yield the maximum oxidation promotion observed to date on the Si(111) surface. The Sm chemisorption process, that follows a peculiar two-step sequence on Si(111) and GaAs (110) surfaces is examined. At submonolayer metal coverage Sm atoms are in a mostly divalent state. At higher metal coverages trivalent Sm specis dominate. At least in the case of Si the oxidation promotion effect appears related to the appearance of the trivalent state. This complex chemisorption process is still far from being completely understood. In this paper we present a simple experimental technique to study the electronic structure of metals in cluster or thin film form on ideally inert substrates. We apply this technique to Sm and we make systematic comparisons of the results for Sm chemisorption onto semiconductors surfaces and Sm adsorption onto inert substrates (solid Xe). In this first preliminary paper we give a very brief summary of the experimental technique and present selected results on cluster-size induced valence transition and on size-dependent metal screening during Sm adorption on Xe. Keywords: Samarium; Silicon; Xenon: Clusters; Metal semiconductor interfaces.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1985
- Accession Number
- ADA163406
Entities
People
- A. Franciosi
- C. Caprile
- C. G. Olson
- D. Wielickza
Organizations
- University of Minnesota