United States of America As Represented by the Secretary of the Air Force

George G Bryant

William M Higgins

David F Bliss

Meckie T Harris

Alton F Armington

New single crystals of ZnGeP.sub.2 are grown by a chemical vapor transport process from bulk synthesized polycrystalline ZnGeP.sub.2 using the LEK process with a controlled injection of phosphorus. The synthesis of the bulk is based on direct injection of phosphorus through a B.sub.2 O.sub.3 encapsulant and reaction with the zinc germanium melt, resulting in synthesis of a large melt (350 g) of ZnGeP.sub.2. When crystallization is followed by cooling the congruent melt down through the .alpha.-.beta. transition temperature (952.degree. C.) as is typical for bulk growth processes, the result is the growth of partially disordered material. This material is placed in a two zone heated furnace where iodine is used to transport the intermediate product to the growth zone where the single crystals grow, at a temperature below the .alpha.-.beta. phase transition. The resulting crystals produced contained a second cubic phase, which has not been reported previously.

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Waltham, MA, United States of America

George G Bryant