1. nanotech@surfaces laboratory, Empa − Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
2. Faculty of Chemistry and Food Chemistry, and Center for Advancing Electronics Dresden, Technical University of Dresden, 01069 Dresden, Germany
3. Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
4. Department of Synthetic Materials and Functional Devices, Max Planck Institute of Microstructure Physics, 06120 Halle, Germany