Structural and optical properties of Ag2S thin films prepared by spray pyrolysis H. Dlala, M. Amlouk, S. Belgacem, P. Girard and D. Barjon Eur. Phys. J. AP, 2 1 (1998) 13-16 Published online: 15 April 1998 DOI: 10.1051/epjap:1998162