1. Hasselt University, Institute for Materials Research (IMO), Universitaire Campus, Building D, B-3590 Diepenbeek, Belgium
2. Molecular Electronics, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen, The Netherlands
3. IMEC, Division IMOMEC, Universitaire Campus, Wetenschapspark 1, B-3590 Diepenbeek, Belgium