Electrical properties of liquid Ge-Se alloys

The conductivities of liquid Ge1-cSec 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 GeSe2 gives rise to an abrupt increase in thermopower. The electrical behaviour of liquid Ge1-cSec alloys with c less than or equal to 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 GeSe2 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 GeSe2.