Temperature Dependence of Thermal Transport Properties of GeSeSb Chalcogenide Glasses

Abstract

Measurements of the effective thermal conductivity $(\lambda _{\mathrm{e}})$ and effective thermal diffusivity $(k_{\mathrm{e}})$ of $\hbox {Ge}_{30-x}\hbox {Se}_{70}\hbox {Sb}_{x}\,(x = (10, 15, 20$, and 25) at. wt.%) chalcogenide glasses have been carried out in the temperature range from room temperature to above the glass transition temperature using the transient plane source technique. In the heating process, variations of $\lambda _{\mathrm{e}}$ and $k_{\mathrm{e}}$ are observed. Both quantities remain approximately constant in the temperature range from room temperature to $160\,^{\circ }$C, beyond which a linear increase is observed and they reach a maximum in the vicinity of a critical temperature called the glass transition temperature $(T_{\mathrm{g}})$. It is interesting to note that $\lambda _{\mathrm{e}}$ and $k_{\mathrm{e}}$ decrease above the glass transition temperature of the glasses. Such a type of behavior can be explained on the basis of structural changes occurring in $\hbox {Ge}_{30-x}\hbox {Se}_{70}\hbox {Sb}_{x}\,(x = (10, 15, 20$, and 25) at. wt.%) chalcogenide glasses. Results also indicate that both $\lambda _{\mathrm{e}}$ and $k_{\mathrm{e}}$ increase with increasing weight percentage of Sb. This is because of an increase of the weak bond density in the glassy system with the addition of Sb.