DC conductivity of GeSeAg glasses at room temperature

Ionic conducting glasses are used as electrolytes in electrochemical applications (microbatteries, sensors, etc.). An interesting superionic amorphous alloy is Ge-Se-Ag where the conducting species is the Ag+ ion. This system is a good glass forming material which does not need high cooling velocities in a wide concentration range in the Se-rich corner. A maximum Ag content of 30 at.% could be introduced into a Se-rich sample with the composition GeSe3 while still retaining the vitreous character. X-ray scattering curves are characterised by a first scattering peak (FSP) located at q approximate to 1 Angstrom(-1) which corresponds to an intermediate range order [J. Non-Cryst. Solids 273 (2000) 30]. The fundamental structural unit of the glass is the GeSe4/2 tetrahedra. In this work, we study the electric behaviour of the amorphous GeSeAg system. Glasses of the (GeSe3)(100-x)Ag-x system were prepared in the composition range from x = 0 to 25 at.%. The electrical characterisation was performed using AC voltages with frequencies ranging from 100 Hz to 100 KHz. The conductivity (sigma approximate to 10(-4) Omega(-1) cm(-1) for x = 25 at room temperature) shows a monotonous decrease with decreasing Ag concentration. We discuss the relation between the glass structure and their electrical properties. (C) 2003 Elsevier Science B.V. All rights reserved.