1. T. Hisamatsu, T. Aburaya, and S. Matsuda, Proc. 2nd World Conf. Exhib. on Photovoltaic Solar Energy Conversion (Luxembourg: Joint Research Centre, European Commission, 1998), pp. 3568–3571.
2. A. Jasenek, U. Rau, T. Hahn, G. Hanna, M. Schmidt, M. Hartmann, H.W. Schock, J.H. Werner, B. Schattat, S. Kraft, K.-H. Schmid, and W. Bolse, Appl. Phys. A 70, 677 (2000).
3. T. Tanaka, T. Ohshima, H. Itoh, S. Okada, A. Wakahara, and A. Yoshida, Jpn. J. Appl. Phys. Suppl. 39-1, 192 (2000).
4. T. Tanaka, Y. Demizu, T. Yamaguchi, and A. Yoshida, Jpn. J. Appl. Phys. 35, 2779 (1996).
5. M. Yamaguchi, C. Uemura, A. Yamamoto, and A. Shibukawa, Jpn. J. Appl. Phys. 23, 302 (1984).