1. IEK-5 Photovoltaics Forschungszentrum Jülich GmbH 52425 Jülich Germany
2. Faculty of Electrical Engineering and Information Technology RWTH Aachen University 52074 Aachen Germany
3. Novosibirsk State University 630090 Novosibirsk Russia
4. Kutateladze Institute of Thermophysics SB RAS 630090 Novosibirsk Russia
5. Institute for Solar Energy Systems Guangdong Provincial Key Laboratory of Photovoltaic Technology School of Physics Sun Yat-Sen University Guangzhou 510275 P.R. China
6. Faculty of Engineering and CENIDE University of Duisburg-Essen 47057 Duisburg Germany