1. Foundation for Research and Technology Hellas, Institute of Electronic Structure and Laser, Road to Voutes, Heraklion 71110, Crete, Greece
2. Department of Materials Science and Technology, University of Crete, Heraklion 71300, Crete, Greece
3. Ecole Supérieure de Physique et Chimie Industrielles, Matière Molle et Chimie, 10 Rue de Vauquelin, Paris 75005, France
4. IBM, Hudson Valley Research Park, East Fishkill, NY 12533, USA