1. Helmholtz-Zentrum Dresden-Rossendorf; Institute of Ion Beam Physics and Materials Research; Bautzner Landstraße 400 D-01328 Dresden Germany
2. Institute for Solid State Electronics; Vienna University of Technology; Floragasse 7 A-1040 Vienna Austria
3. Center for Advancing Electronics Dresden (cfaed); Technische Universität Dresden; 01062 Dresden Germany