Preparation and properties of silicon telluride

Abstract

The phase diagram for the silicon-tellurium system has been examined primarily by the methods of thermal analysis and metallographic examination. Only a single compound, Si 2Te 3, with an incongruent melting point of 892°C, was found to form in the solid state. The compound SiTe was identified only in the vapor phase. Single phase Si 2Te 3 was prepared by quenching from the liquid phase and annealing, and by vacuum sublimation of excess Te from samples containing no unreacted Si. Red single crystal platelets of Si 2Te 3 were grown by vapor transport in evacuated quartz capsules. Unprotected samples of Si 2Te 3 hydrolyzed slowly when in contact with air. Si 2Te 3 was found to be a p-type semiconductor with a band gap of 2·0 eV, an electrical resistivity normally in the 10 1–10 4 Ω-cm range, a thermal conductivity of 4–5 mW °C-cm , and a density of 4·5 g cm 3 .