Heterogeneity of molecular structure of Ag photo-diffused Ge30Se70 thin films

Silver photodiffusion in thin Ge30Se70 films is investigated in order to understand the structure forming in the Ge–Se host after introduction of Ag in it. Optical micrographs point towards formation of homogeneous films after deposition of the Ge–Se material on glass substrate. This structure changes and occurrence of heterogeneous regions is imaged after Ag is introduced into the Ge–Se host. Raman spectroscopy provides data about the development of the structural organization in the host in depth. It confirms that while the initial non-doped films are organized in a structure corresponding to the bulk material with analogous composition, after Ag photodiffusion, the structure on the interface Ag/Ge30Se70 film is identified as being amorphous Ag8GeSe6 which continuously changes in depth to structure of Ge-rich material. Raman spectra testify that Ag distribution reaches the bottom of the hosting Ge30Se70 films. ! 2008 Elsevier B.V. All rights reserved. PACS: 78.30.j; 61.10.Nz