1. Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, Dübendorf 8600, Switzerland
2. Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin D-14109, Germany
3. Institute of Physics, Martin-Luther-University Halle-Wittenberg, Halle 06120, Germany
4. Ångström Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, Uppsala 75121, Sweden
5. School of Microelectronics, Shandong University, Jinan 250100, China
6. Electron Microscopy Center, Empa-Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, Dübendorf 8600, Switzerland