Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 62: Posters: Surface Reactions and Dynamics, Nanostructures
O 62.13: Poster
Wednesday, April 2, 2014, 17:30–21:00, P1
Investigating Very Low Energy Electron Transmission through Thin Metallic Films — •Daniel Panzer and Gerd Schönhense — Institut für Physik, Johannes-Gutenberg Universität, 55128 Mainz
The inelastic mean free path of electrons in matter is strongly energy dependent (it increases steeply at low energies <20eV [1]), and spin sensitive [2,3]. In the present work we use an imaging system that projects an electron optical image from a thermal or photoemitter onto an ultrathin metallic film and then watch the transmitted electrons using a standard Photo Emission Electron Microscope (PEEM) column. This allows for a wide range of combinations of different emitters and thin films. Thermionic emitters like BaO and Y2O3 provide high intensity to rate transmission for thicker sample films or multi-layer systems. Threshold photoemission provides a smaller emission energy width to better evaluate transmission of samples like Au, Pt and Pd at different kinetic energies. A pulsed photoemitter in combination with a delay line detector facilitates time-of-flight measurements to distinguish between different scattering processes. A uniformly magnetized ferromagnetic film should eventually enable spin-filtering an electronic image coming from a spin-polarized photoemitter.
References:
[1] M.P. Seah, W.A. Dench, Surf. a. Interface Analysis (1979), 1(1):2.
[2] W. Weber, S. Riesen, H.C. Siegmann, Science 291 (2001), 1015
[3] P. Dey, W. Weber, J. Phys.: Condens. Matter 23 (2011), 473201