CRYSTAL GROWTH OF CADMIUM TELLURIDE (CDTE) BY THE HEAT EXCHANGER METHOD (HEM)

CADMIUM TELLURIDE (CDTE) CRYSTALS ARE REQUIRED FOR A NUMBER OF APPLICATIONS. ONE OF THE MAIN REQUIREMENTS IS AS MODULATORS OF 10.6 UM CO2 LASER RADIATION, ESPECIALLY IN LASER RADAR. A NUMBER OF CRYSTAL GROWTH PROCESSES HAVE BEEN USED; HOWEVER, ONLY SMALL CRYSTALS WITH LOW YIELDS HAVE BEEN GROWN. IT IS INTENDED TO USE A NEW CRYSTAL GROWTH PROCESS, THE HEAT EXCHANGER METHOD (HEM), AND SHOW FEASIBILITY OF GROWTH FOR CDTE CRYSTALS. SOME OF THE ADVANTAGES OF HEM ARE SUBMERGED SOLID-LIQUID INTERFACE, INDEPENDENT CONTROL OF SOLID AND LIQUID GRADIENTS WITHOUT MOVEMENT, UNIFORM GRADIENTS AT THE CONVEX SOLID-LIQUID INTERFACE, FLEXIBILITY AND PRECISE CONTROL OF HEAT EXCHANGER TEMPERATURE AND IN-SITU ANNEALING OF THE CRYSTAL AFTER GROWTH. THE COMBINATION OF THESE FEATURES AND THE ABILITY TO SCALE UP IN SIZE ALLOW IMPORTANT ADVANTAGES TO HEM. DURING THE PROPOSED PHASE I IT IS INTENDED TO SHOW FEASIBILITY OF GROWTH OF CDTE CRYSTALS IN SEALED QUARTZ AMPULES. ALTERNATE CRUCIBLE MATERIALS AND ENCAPSULATED GROWTH CAN BE EASILY ADAPTED IN THE HEM SYSTEM.