1. G. Untila, T. Kost, A. Chebotareva, M. Zaks, A. Sitnikov, and O. Solodukha, in Proceedings of the 21st European Photovoltaic Solar Energy Conference (Dresden, 2006), p. 1199.
2. H. Kobayashi, Y.-L. Liu, Y. Yamashita, J. Ivanco, S. Imai, and M. Takahashi, Sol. Energy 80, 645 (2006).
3. T. Nagamoto, M. Endo, and O. Omoto, Jpn. J. Appl. Phys. 18, 1103 (1979).
4. H. Kobayashi, H. Mori, T. Ishida, and Y. Nakato, J. Appl. Phys. 77, 1301 (1995).
5. G. Untila, T. Kost, A. Chebotareva, M. Zaks, A. Sitnikov, and O. Solodukha, in Proceedings of the 22nd European Photovoltaic Solar Energy Conference (Milan, 2007), p. 1641.