1. Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
2. Laboratory for Molecular Surfaces and Nanotechnology−CSGI, Viale A. Doria 6, 95125 Catania, Italy
3. National Interuniversity Consortium for Materials Science and Technology (I.N.S.T.M.) Research Unit of Catania, Viale A. Doria 6, 95125 Catania, Italy
4. Department of Electrical, Electronics and Informatics Engineering, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy