Structural and optical properties of Ge nanocrystals grown by RF-sputtering technique P. Caldelas, S. Yerci, A. G. Rolo, A. Chahboun, O. Conde, E. Alves, M. J. M. Gomes, R. Turan 28th. International Conference on the Physics of Semiconductors-28thICPS Conference Proceedings, July 2006, Vienna, Austria. CD ROM publication.