Derivation of a relation between the conduction mechanism and chemical bonding of amorphous Ge<inf>15</inf>Se<inf>85-x</inf>Ag<inf>x</inf> alloys

Abstract

A critical analysis of the existing theories of AC conduction in amorphous Ge15Se85-xAgx films with x=0, 10 and 20 has been made. Measurements of the conductivity and the dielectric constant have been made at various frequencies from 100Hz to 100kHz and at various temperatures from 303 to 393·K. The AC conductivity of these alloys is found to be temperature dependent and to obey the Aωs law. The conductivity and dielectric behavior of these glasses have been explained on the basis of the correlated barrier hopping model, as well as the effect of Ag atoms on the homonuclear bonds. The effect of both the chemical composition and the nature of chemical bonding of amorphous Ge-Se-Ag alloyed samples is analyzed using a simple consideration based on the coordination number Nco. The coordination number has been used for the estimation of the cohesive energies of these glasses, assuming simple additivity of the bond energies. It was found that there is a good correlation between experimental and theoretical results. © 2002 Elsevier Science B.V. All rights reserved.