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D. Kovacs, A. Golczewski, G. Kowarik, F. Aumayr, D. Diesing:
"Low-energy ion-induced electron emission in metal-insulator-metal sandwich structures";
Physical Review B, 81 (2010), 0754111 - 07541112.

An Ag-AlOx-Al sandwich structure is used to investigate the electronic excitation induced by Ar+ ions at the
surface of the top 15 nm Ag film. The internal electron emission yield, i.e., the number of electrons emitted per
impinging ion into the bottom Al film, is determined as a function of the kinetic energy of the ions in the range
of 300-6000 eV. A comparison to the external electron emission yield, i.e., the number of electrons per
projectile ejected into the vacuum, reveals two interesting aspects. First, unlike in the external emission, no
significant contribution of the potential energy to the internal electron emission yield is observed. Second, the
kinetic part of the electron emission yield exceeds the external one over the entire energy range. Another
interesting result is that the internal emission yield shows a power-law dependence on ion kinetic energy. A
Monte Carlo simulation, based on a simple theoretical treatment of the kinetically induced electron emission,
supports the experimental findings. Finally, we discuss the influence of excitation properties e.g., anisotropy
as well as of device properties e.g., film thickness, barrier height on the computed electron emission yields.