1. Imec, Kapeldreef
75, Leuven B-3001, Belgium
2. Department of Metallurgy and Materials
Engineering (MTM), KU Leuven, Kasteelpark Arenberg 10, Leuven B-3001, Belgium
3. Department of Solid State Sciences, Ghent University, Krijgslaan
281/S1, Gent B-9000, Belgium
4. Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
5. Department of Electronics
and Information Systems, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium