Optical and electrical investigations of amorphous Ag-Ge metallic alloy films☆

Abstract Thin films of amorphous Ag-Ge metallic alloys with germanium concentrations of 26–37 at.% were prepared by co-evaporation under ultrahigh vacuum onto glass substrates maintained at low temperatures (10–20 K). The results of in situ d.c. electrical resistance measurements and of optical measurements in the 0.6–4.5 eV range are described and discussed. The film structure at room temperature was investigated by electron microscopy and diffraction. The optical data are analysed in terms of a quasi-free-electron model (Drude model). The characteristic parameters (the effective number and the relaxation time) are compared with those previously obtained for amorphous Au-Ge alloys; the role of (s,p)-d hybridization is discussed.