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. PACS: 78.30.j;61.10.Nz;