Microsc. Microanal. Microstruct. 2, 191-201 (1991)
DOI: 10.1051/mmm:0199100202-3019100

Investigation of metal cluster layers by EELS

Hellmut Seiler¹, Ulrich Haas¹, Karl-Heinz Körtje² et Bernd Ocker<sup>1

1</sup>  Institut für Physik, Universität Hohenheim, D-7000 Stuttgart-70, Germany
²  Institut für Zoologie, Universität Hohenheim, Garbenstr. 30, D-7000 Stuttgart-70, Germany

Abstract
The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared homogeneous silver layers with cluster layers of small silver particles with diameters of about 50 nm deposited on thin Pioloform foils, respectively. The EELS spectra of the particles seem to be different in the low loss region from the spectra of homogeneous Ag layers. This can be attributed to the influence of the carbon foil and the packing density of the particles. Investigations of Sn particles on Pioloform foils were performed to obtain additional information. Furthermore, we studied the optical behavior of different layers of Ag by Photoacoustic Spectroscopy. For particles, the plasma resonance of conduction electrons gives rise to an absorption peak, which shifts towards longer wavelengths for increasing packing density.

PACS
0781 - Electron and ion spectrometers.
73 - Electronic structure and electrical properties of surfaces, interfaces, thin films, and low-dimensional structures.
78 - Optical properties, condensed-matter spectroscopy and other interactions of radiation and particles with condensed matter.

Key words
EEL spectroscopy -- Metal cluster -- Silver -- Size effect -- Photoconductivity -- Transmission electron microscopy -- Scanning electron microscopy -- High resolution -- Physical properties -- Packing density


© EDP Sciences 1991