1. School of Electrical & Computer Engineering Ben-Gurion University of the Negev POB 653 Beer-Sheva 8410501 Israel
2. International Iberian Nanotechnology Laboratory (INL) 4715-330 Braga Portugal
3. Institut de Microelectrònica de Barcelona (IMB-CNM CSIC) Bellaterra 08193 Catalonia Spain
4. The Ilse-Katz Institute for Nanoscale Science & Technology Ben-Gurion University of the Negev POB 653 Beer-Sheva 8410501 Israel