Abstract: Disclosed is a method for making large, essentially crack-free crystals in a container coated with inert particulate silica. The particulate coating covers the interior wall of the container and prevents adhesion of the crystal to the wall and acts like a cushion to avoid cracking of the crystal or the container. It also serves as a barrier to prevent migration of impurities from the container wall into the crystal structure. The coating is formed by heating a silica-forming gaseous mixture flowing through the container, with components of this mixture either reacting to form the coating.

Abstract: A method for producing a large high-quality single crystal of Cadmium-Indium-Telluride is disclosed wherein a stoichiometric crystal is produced from a non-stoichiometric melt composition. An initial melt composition corresponding to approximately 62 mole % to 90 mole % In.sub.2 Te.sub.3 and 38 mole % to 10 mole % CdTe, respectively, is prepared and sealed in an evacuated ampoule and then heated to completely melt the mixture. Growth of a single crystal of CdIn.sub.2 Te.sub.4 is initiated and maintained from the non-stoichiometric melt mixture by lowering the melt through its corresponding phase-equilibrium melting point. Upon cooling to room temperature, the large single crystal so produced is removed from the ampoule.