1. Laboratory of Semiconductor Materials, Institute of Materials, École Polytechnique, Fédérale de Lausanne, 1015 Lausanne, Switzerland
2. EULITHA, Studacherstrasse 7B, 5416 Kirchdorf, Switzerland
3. FHNW University of Applied Sciences and Arts Northwestern Switzerland, School of Engineering, Switzerland
4. Department of Materials Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
5. Institute of Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland