Regensburg 2004 – wissenschaftliches Programm
O 44.1: Vortrag
Freitag, 12. März 2004, 11:15–11:30, H38
Spectroscopy of ion beam induced electronic excitations at surfaces — •Stefan Meyer1, Detlef Diesing2, and Andreas Wucher1 — 1Institut für experimentelle Physik, Universität Duisburg- Essen, 45117 Essen — 2Institut für Schichten und Grenzflächen 3, Forschungszentrum Jülich, 52425 Jülich
We investigate the electronic excitation of a solid surface that is generated by the introduction of kinetic energy in form of fast ion bombardment. In particular, hot electrons are detected which are excited to energies below the work function and therefore cannot leave the surface. The ballistic mean free path of these weakly excited electrons is of the order of 10 nm. The sample is therefore prepared as a 20 nm thin film constituting the front electrode of a metal- insulator- metal tunnel junction. The hot electrons reaching the junction lead to a tunneling current that can be measured. By applying a variable DC- voltage across the junction it is possible to measure the energy distribution of excited electrons, depending on ion beam parameters such as ion energy or ion species.