1. Institute for Solid State Electronics, TU Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
2. Center for Micro- and Nanostructures, TU Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
3. Central European Institute of Technology, Brno University of Technology, Purkynova 123, 612 00 Brno, Czechia