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Metallic nanoparticles have been produced on vitreous carbon substrates by means of thermal evaporation. From pictures of the particles. made by a high-resolution scanning electron microscope (HRSEM). a semispherical shape is suggested due to the total mass of deposited material. Atomic force microscopy (AFM) has been applied to this sample in order to get direct topographic information. The AFM has been operated with normal and super tips, the latter having a smaller cone angle and radius, thus following more precisely the contours of an object. Simultaneously lateral-force microscopic (LFM) images have been recorded. Major differences between the contents of HRSEM-and AFM-images are considered. emphasizing the important influence of the tips' geometry. Both the AFM and LFM line scans have been compared with and have qualitatively agreed with those calculated under simplifying assumptions.

Electron energy loss spectroscopy (EELS) in a transmission electron microscope (TEM) and photoacoustic spectroscopy (PAS) has been used to study the electronic structure of small Ag, In and Au particles, deposited on thin carbon foils, quartz supports or as self-supporting layers, respectively.In the low energy-loss region the EELS spectra of Ag particles with diameters of ca. 50 nm are different from the spectra of the homogeneous Ag layers, mainly owing to the influence of the carbon foil. By decreasing the packing density of the Ag particles, a shift of the plasma losses to lower energies is observed in the energy region 10eV. The optical behaviour of homogeneous metallic and small particle layers on thin quartz supports was studied by PAS in the ultraviolet/visible (UV/VIS) spectral region. The homogeneous layers, e.g. of Ag, show, in the UV range, the well known change of reflectance due to an interband transition of bare silver. For Ag particle layers surface plasma resonances are excited. With increasing packing density of the particles the absorption peak observed is red-shifted and becomes broader, whereas the results of EELS in the low energy-loss region revealed a shift to higher energies.To obtain additional information investigations of In and Au particles were performed.

Abstract. 2014 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.

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