Vapor pressure scanning implications of CdTe crystal growth

Vapor pressure scanning (VPS) is a direct high precision method of investigation of the composition of nonstoichiometric crystals at high temperatures. It is based on experimental measurements of the vapor pressure, from which three-dimensional P-T-X (pressure-temperature-composition) range of existence of the crystalline phase is constructed. For CdTe the accuracy of the VPS determination of nonstoichiometry was proved to bt: within 10(-4) at% for temperatures up to the melting point (1365 K). In this communication it is shown how to apply experimental P-T-X phase equilibrium data for preparation of the material with controlled composition, either stoichiometric or with a certain deviation from stoichiometry. Different technologies are analyzed: vapor phase growth, vertical, horizontal and high pressure Bridgman, (C) 1999 Elsevier Science B.V. All rights reserved.