METHOD OF PREPARING COMPOUND LiInS MONOCRYSTALS Russian patent published in 2002 - IPC

FIELD: crystal growing. SUBSTANCE: invention relates to preparing monocrystalline alkali metal thioindates with structure A^IB^IIICVI2

, in particular monocrystalline compound LiInS₂, employed in nuclear engineering and as emission transformer. Method consists in that LiInS₂ monocrystals are prepared by directed crystallization in evacuated container after synthesis of LiInS₂ in refractory bowl placed in evacuated container. Mixture of lithium, indium, and sulfur taken in stoichiometric proportions is heated to temperature above melting point of LiInS₂. Simultaneously, a cold zone (up to 450 C) is created in container. Directed crystallization is accomplished by displacing container within vertical gradient zone of heater at velocity 0.1 to 2 mm/h. Further, grown crystal is annealed in the same container under isothermal conditions. To than end, crystal and cold zone of container with volatile components condensed on its walls are heated to temperature not exceeding melting point of LiInS₂, aged during 10-12 h, and cooled to ambient temperature. EFFECT: increased size of crystals (20 mm in diameter and 50 mm long) showing high optical quality. 2 cl, 1 dwg