1. Institute for Microelectronics and Microsystems, IMM-CNR, Via Monteroni, 73100 Lecce, Italy
2. Institute of Nanotechnology, NANOTEC-CNR, Via Monteroni, 73100 Lecce, Italy
3. Institute for Microelectronics and Microsystems, IMM-CNR, Via Del Fosso Del Cavaliere, 100, 00133 Rome, Italy