Arsenic triselenide: preparation and electrical conductivity at high temperatures

Abstract

Arsenic triselenide and other chalcogenide glasses have been prepared rapidly from the elements by heating at temperatures in the range 900–1500 °C under argon at high pressure in an internally heated pressure vessel. The electrical conductivity of liquid arsenic triselenide has been measured over the temperature range 187–1425 °C under a high pressure of argon. Below 600 °C, the plot of log σ against 1/T is linear and confirms semiconductive behaviour. In the range 600–1425 °C, the conductivity initially shows a marked increase with temperature, but near 1400 °C it tends to become constant. The explanation offered qualitatively for the high-temperature behaviour, is that the selenide changes from a semiconductor to a metallic conductor as the polymeric structure of the liquid is thermally destroyed. The results are compared with those for liquid selenium.