1. Istituto Nazionale di Fisica Nucleare (INFN), 10125 Torino, Italy
2. Physics
Department, University of Torino, 10125 Torino, Italy
3. “Nanostructured
Interfaces and Surfaces” Inter-departmental Centre, University of Torino, 10125 Torino, Italy
4. Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Torino Unit, 10125 Torino, Italy
5. Department
of Drug Science and Technology, University of Torino, 10125 Torino, Italy
6. Institute
of Electron Devices and Circuits, Ulm University, 89081 Ulm, Germany