Electrical Properties of Liquid Ge–Se Alloys

Abstract

The conductivities of liquid Ge 1- c Se c alloys on the Ge-rich side decrease monotonically with increasing Se composition. The composition dependence of conductivity at 1023 K exhibits a broad minimum at the composition c =0.72. The composition dependence of thermopower exhibits a maximum and a minimum with positive values at the compositions c =0.55 and 0.6, respectively. The addition of Se to liquid GeSe 2 gives rise to an abrupt increase in thermopower. The electrical behaviour of liquid Ge 1- c Se c alloys with c ≦0.3 was understood from the decrease in the conduction electrons due to the formation of chemical bonds. The conductivity and thermopower near the stoichiometric GeSe and GeSe 2 were analyzed by assuming an energy-dependent conductivity. The conductivity gap at 1023 K varies widely from about 0 eV for liquid GeSe to about 1.4 eV for liquid GeSe 2 .