Crystallization effects in annealed thin GeS2 films photodiffused with Ag

We have investigated the diffusion products occurring after photodiffusion of Ag in GeS2 films at room temperature and after annealing up to 430 degrees C. Quantitative data regarding the host film composition and the amount of diffused silver has been gathered using Rutherford backscattering spectrometry. The structure of the glassy host and the changes appearing after silver photodiffasion and annealing are characterized using Raman spectroscopy. The crystalline diffusion products are depicted and their size calculated using X-ray diffraction. We have found that silver reacts with the host to form Ag2S and Ag2GeS3 and this leads to formation of Ge-rich backbone and overall nanostructured heterogeneous medium. Annealing at temperatures close to the glass transition temperature affects the backbone and brings about the appearance of a new diffusion product - Ag8GeS6. (C) 2007 Published by Elsevier B.V.