1. Proc. 5th Int. Photovoltaic Science and Engineering Conf. (PVSEC-5), Nov. 1990, Kyoto, Japan
2. Proc. 21st IEEE Photovoltaic Specialists Conf., May 1990, Kissimmee, USA
3. Proc. 9th E.C. Photovoltaic Solar Energy Conf., Sept. 1989, Freiburg, FRG
4. H. Miki et al.: In Amorphous Silicon Semiconductors ? Pure and Hydrogenated, ed. by A. Madan, M. Thompson, D. Adler, Y. Hamakawa (Mater. Res. Soc. Proc. 95, Pittsburgh, PA 1987) p. 431
5. I. Shimizu: J. Non-Cryst. Solids 77 & 78, 1363 (1985)