1. Institute of Physics, Academy of Sciences of the Czech Republic; Cukrovarnicka 10; 16253 Prague Czech Republic
2. Czech Technical University; Faculty of Nuclear Science and Physical Engineering; Trojanova 13 1200 Prague Czech Republic
3. Ecole Polytechnique Federale de Lausanne (EPFL), Institute of Microengineering (IMT); Photovoltaic and Thin-Film Electronics Laboratory, Rue De La Maladiere 71b; 2000 Neuchatel Switzerland
4. University of Ljubljana, Faculty of Electrical Engineering; Laboratory of Photovoltaics and Optoelectronics; Trzaskacesta 25 1000 Ljubljana Slovenia