Electrical and thermal properties of chalcogenide glass system Se₇₅Ge_25−x Sb _x

Abstract

The dc and thermal conductivities of five different compositions of the chalcogenide glass system Se₇₅Ge_25−x Sb _x have been studied in a temperature range below T _g. The dc conductivity results indicate that each composition has a single activation energy in the considered temperature range. The coefficient of thermal conductivity increased linearly with temperature below T _g for the compositions investigated. The increase of Sb content in the chalcogenide glass system leads to an increased coefficient of electrical conductivity σ, an increased coefficient of thermal conductivity ψ, and to a decreased activation energy E _σ and pre-exponential factor σ₀. The observed compositional dependencies of σ and E _σ have been correlated with the increase of weak bond density and the decrease of covalent bond density in the structure of the compositions investigated with increasing Sb content at the expense of Ge content. The decrease in σ₀ and the increase in ψ has been, respectively, correlated with the decrease in mobility and the increase in phonon velocity.