1. STMicroelectronics, Stradale Primosole, 50, 95121 Catania, Italy
2. Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy
3. INSTM U.d.R. of Catania, Viale Andrea Doria 6, 95125 Catania, Italy
4. CNR-IMM, Zona industriale Strada VIII, 5, 95121 Catania, Italy