SOME ELECTRICAL TRANSPORT STUDIES ON COMPOUNDS OF TI-TE SYSTEM

Galvanomagnetic, thermoelectric and electrical conductivity measurements were made on single crystal specimens of Tl2Te3, TlTe and γ-phase in the temperature range from 77° K up to 500 to 700° K. All crystals were found to be of p-type conductivity. Measurements of the electrical conductivity versus composition have revealed that γ-phase represents solid solutions of Tl and Te in the compound with formula Tl5Te3. Also, it has been found that both TlTe and γ-phase samples exhibit a metallic behaviour in contrast to Tl2Te3, which has semiconducting properties. In the intrinsic conduction region a thermal energy gap of a 0.68 ± 0.03 eV was found, which was compared with that obtained from optical transmission measurements. The electrical properties of Tl-Te compounds are discussed on the basis of the general valence rule. © 1969 Chapman and Hall.