1. Advanced Microelectronic Center Aachen (AMICA), AMO GmbH, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany
2. CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
3. Dipartimento di Ingegneria dell’Informazione, Università di Pisa, Via Caruso 16, Pisa 56122, Italy
4. Chair of High Frequency Electronics, RWTH Aachen University, Templergraben 55, 52056 Aachen, Germany