Ag-Conducting Chalcogenide Glasses: Applications In Programmable Metallization Cells

Recent work performed on the Ag—Ge—Se glass system, a potential candidate to the fabrication of electrical memories, is reviewed in this paper. The combined investigation of the electrical conductivity by complex impedance spectroscopy and the microstructure by field emission scanning electron microscopy and electric force microscopy indicated that phase separation is a key to the understanding of the electrical properties. An ab-initio molecular dynamic simulation along with neutron diffraction experiments performed on the D4 instrument at the Institut Laue Langevin helped to understand the short and intermediate range order of the glasses. Under dynamic conditions, a thermodiffraction study carried out on the D1B instrument at the ILL evidenced the existence of a new Ag₂GeSe₃ phase at high temperatures. This phase partially decomposed with time or when the temperature decreased to GeSe₂ and a new Ag₁₀Ge₃Se₁₁ phase which can be found in the compound at room temperature.