Thermoelectric Study of Liquid Semiconductor Solutions of Tellurium and Selenium

Abstract

The thermoelectric properties of liquid tellurium have been studied at temperatures ranging between 400° and 500°C both for pure tellurium and for solutions containing up to 20% (by weight) of selenium. This included measurements of the electrical conductivity σ, the Seebeck coefficient α, and the dimensionless figure of merit γ(=α²σT/κ) and from these the thermal conductivity κ was derived. The measurements were made entirely by electronic methods in a sealed Pyrex tube containing platinum and platinum—rhodium leads. The figure of merit was obtained by the small area contact method devised by one of the authors. For liquid tellurium, our results for α, σ, and κ agreed with values which have been obtained previously by other investigators. The unusually large value of κ observed in liquid tellurium is found to decrease upon addition of selenium. This, and the behavior of α and σ indicate that selenium tends to reduce the concentration of electrons in comparison to that of the holes. At higher concentrations of selenium, phenomena are observed which seem to be related to the motion of ions.