1. F. Dimroth, W. Guter, J. Schöne, E. Welser, M. Steiner, E. Oliva, A. Wekkeli, G. Siefer, S. P. Philipps, and A. W. Bett, in Proceedings of the 24th PVSEC (Hamburg, Germany, 2009) p. 1038.
2. J. Schone, S. Philipps, M. Steiner, G. Siefer, A. Wekkeli, E. Welser, E. Oliva, A. W. Bett, F. Dimroth, and W. Guter, Appl. Phys. Lett. 94, 223504 (2009).
3. C. Algora, I. Rey-Stolle, I. Garcia, B. Galiana, M. Baudrit, P. Espinet, E. Barrigon, and J. R. Gonzalez, in Proceedings of the 34th IEEE Photovoltaic Specialists Conference (PVSC) (Philadelphia, 2009), p. 1571.
4. H. Cotal, C. Fetzer, J. Boisvert, G. Kinsey, R. King, P. Hebert, H. Yoon, and N. Karam, Energy Environ. Sci. 2, 174 (2009).
5. V. M. Andreev, V. A. Grilikhes, and V. D. Rumyantsev, Photovoltaic Conversion of Concentrated Sunlight (Nauka, Leningrad, 1989; Wiley, New York, 1997).