Structural and optical properties of Ge-As-Te thin films S. H. Mohamed, M. M. Wakkad, A. M. Ahmed and A. K. Diab Eur. Phys. J. Appl. Phys., 34 3 (2006) 165-171 Published online: 24 June 2006 DOI: 10.1051/epjap:2006061