1. Department of Micro- and Nanoelectronic Systems, TU Ilmenau, Gustav-Kirchhoff-Str. 1, 98693 Ilmenau, Germany
2. Institute of Functional Nanosystems, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany
3. Nanoanalytik GmbH, Ehrenbergstraße 1, 98693 Ilmenau, Germany
4. Lawrence Berkeley National Laboratory, Molecular Foundry, Berkeley, California 94720
5. Institute of Process Measurement and Sensor Technology, TU Ilmenau, Gustav-Kirchhoff-Str. 1, 98693 Ilmenau, Germany