1. H. W. Schock and A. Shah, in Proceedings of 14th European Photovoltaic Solar Energy Conference (Barcelona, Spain, 1997).
2. O. Lundberg, M. Edoff, and L. Stolt, in Abstract Book of Solar World Congress, ISES-2003 (Göteborg, Sweden, 2003), p. 57.
3. T. M. Razykov, Abstract Book of Solar World Congress, ISES-2003 (Göteborg, Sweden, 2003), p. 61.
4. S. D. Tsang, S. H. Wei, A. Zunger, and H. Katayma-Yoshida, Phys. Rev. B 57, 9642 (1998).
5. S. H. Wei, S. D. Tsang, and A. Zunger, Appl. Phys. Lett. 72, 3199 (1998).