1. IHP, Leibniz-Institut für Innovative Mikroelektronik, Im Technologiepark 25, D-15236Frankfurt (Oder), Germany
2. IKZ, Leibniz-Institut für Kristallzüchtung, Max-Born-Straße 2, D-12489Berlin, Germany
3. ESRF, European Synchrotron Radiation Facility, 71, Avenue des Martyrs, CS 40220, 38043Grenoble Cedex 9, France
4. QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJDelft, The Netherlands
5. QuTech and Netherlands Organisation for Applied Scientific Research (TNO), Stieltjesweg 1, 2628 CKDelft, The Netherlands
6. Department of Physics Enrico Fermi, Università di Pisa, Pisa56126, Italy
7. Dipartimento di Scienze, Universita Roma Tre, Roma00146, Italy