1. Laboratory of Nanoscale Biology, Institute of Bioengineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
2. Laboratory of Nano-Bio Instrumentation, Institute of Bioengineering, EPFL, CH-1015 Lausanne, Switzerland
3. Laboratory of Nanoscale Electronics and Structures, Electrical Engineering Institute and Institute of Materials Science, EPFL, CH-1015 Lausanne, Switzerland
4. Laboratory of Quantum Nano-Optics, Institute of Physics, EPFL, CH-1015 Lausanne, Switzerland
5. School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
6. National Institute for Materials Science, 305-0044 Tsukuba, Japan
7. Laboratory for Transport at Nanoscale Interfaces, Empa−Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland