Stoichiometric deviations and partial-pressure measurements in solid-vapour cadmium telluride system

In the frame of a research project aimed at developing a single-crystal-growth technology of cadmium telluride (CdTe) for electrooptics and photorefractive applications, the authors have implemented a laser absorption technique by which the partial pressure of the vapours (Te2(g), Cd(g)) over solid CdTe can be monitored as a function of temperature in the temperature range 500-900 °C. By testing polycrystalline materials of different origins, this technique proved to be a reliable tool for selecting the most suitable polycrystalline CdTe to be used as a source in the physical vapour transport (PVT) growth of CdTe single crystals.