Origin of the photoluminescence shifts in porous silicon H. Elhouichet, B. Bessaïs, O. Ben Younes, H. Ezzaouia and M. Oueslati Eur. Phys. J. AP, 1 2 (1998) 153-157 Published online: 15 February 1998 DOI: 10.1051/epjap:1998130