1. Fraunhofer-Center for Silicon Photovoltaics CSP, 06120 Halle (Saale), Germany
2. Fraunhofer Institute for Microstructure of Materials and Systems IMWS, 06120 Halle (Saale), Germany
3. AnhaltUniversity of Applied Sciences, Faculty EMW, Koethen (Anhalt), Germany
4. Institute of Physics, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany