1. Technology for Thin Film devices, Technische Universitat Berlin, Einsteinufer 25, 10587 Berlin, Germany
2. Institute of Solid State Physics, Technische Universitat Berlin, Hardenberg st. 36, 10623 Berlin, Germany
3. Department Structure and Dynamics of Energy Materials (EM-ASD), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany