1. Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
2. Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
3. Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
4. Institute of Research and Development of Energy from Photovoltaics (IRDEP-CNRS), Chatou 78401, France
5. NextPV, Joint RCAST-CNRS Laboratory, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan