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T. Peters, C. Haake, D. Diesing, D. Kovacs, A. Golczewski, G. Kowarik, F. Aumayr, A. Wucher, M. Schleberger:
"Hot electrons induced by slow multiply charged ions";
New Journal of Physics, 10 (2008), 0730191 - 0730198.

The dissipation of energy following the impact of multiply
charged ions on a polycrystalline metal surface was studied using thin film
metal-insulator-metal junctions as targets. The ions hit the top Ag layer of
a Ag-AlOx-Al junction, where they excite electrons and holes. A substantial
fraction of these charge carriers is transported across the insulating barrier and
can be detected as an internal current in the bottom Al layer. The effects of
potential and kinetic energies on this tunneling yield are investigated separately
by varying the charge state of the Ar projectile ions from 2+ to 8+ for kinetic
energies in the range from 1 to 12 keV. Per impinging ion yields of typically
0.1-1 electrons are measured within the thin film tunnel junction. The tunneling
yield is found to scale linearly with the potential energy of the projectile. In
addition, the tunneling yield shows a strong dependence on the internal barrier
height which can be modified by an external bias voltage.