1. Departament d’Enginyeria Electrònica, Universitat Autònoma de Barcelona 1 , 08193 Cerdanyola del Valles, Spain
2. Advanced Thin Film Technology, Institute of Materials Science, Technische Universität Darmstadt 2 , 64287 Darmstadt, Germany
3. Computer Systems Group, Department of Electrical and Information Engineering, Technische Universität Darmstadt 3 , 64283 Darmstadt, Germany
4. Integrated Electronic Systems, Department of Electrical and Information Engineering, Technische Universität Darmstadt 4 , 64283 Darmstadt, Germany