1. Nanotechnology Group, ETH Zürich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
2. Surface Science & Coating Technologies, Swiss Federal Laboratories for Materials Science and Technology (EMPA), Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
3. Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
4. Laboratory for X-ray Nanoscience and Technologies, Paul-Scherrer-Institute (PSI), CH-5232 Villigen PSI, Switzerland