1. Institute of Microengineering (IMT), Photovoltaics and Thin Film Electronics Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), 2000 Neuchâtel, Switzerland
2. Department of Material Science and Engineering, Stanford University, Stanford, California 94305, United States
3. Interdisciplinary Center for Electron Microscopy (CIME), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland