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M. Simon, A.S. El-Said:
"Surface modifications at and electron emission from insulator surfaces induced by impact of slow highly charged ions";
Vortrag: Seminar Institut für Allgemeine Physik (IAP), TU Wien; 17.10.2006.

Highly charged ions (HCI) carry a large amount of potential energy which is released upon impact on a surface. Since under certain circumstances this can give rise to surface modifications, HCI impact can be considered as a promising tool for future nanostructuring methods. Concerning the approach of slow HCI towards the surface, there is a debate on how the resulting hollow atoms are formed in front of insulator surfaces, since the different dielectric response as compared to a metal surface (lower image charge attraction, limited hole mobility) makes modeling calculations rather ambiguous.
To address both problems from the experimental side, we have constructed an apparatus which allows for irradiation of single crystal targets, e.g., LiF(001), CaF2(111) and Au(111), with slow (v < 1 a.u.) HCI under UHV conditions at different incidence angles. As primary ions we use HCI (up to Hg64+) from the Heidelberg-EBIT. During the interaction we can monitor the primary ion flux and measure the electron yield with an electron number statistics detector, and thus get information on the hollow atom formation process. After irradiation the HCI induced nanostructures are investigated by atomic force microscopy (AFM). Results from several experimental campaigns in Heidelberg will be presented.