EFFECT OF TEMPERATURE-FIELD ON GROWTH STABILITY

The effect of temperature field of the growth system on the morphology of the Pb0.8Sn0.2Te solid-vapour interface is studied. The first stag e of seed formation and growth in a novel method of self nucleation an d growth without contact with ampoule wall [K. Grasza et al., J. Cryst al Growth 123 (1992) 519] is discussed. The seeds were grown in differ ent temperature profiles with the same growth velocity and at the same temperature. The resulting crystals were always strongly faceted, wit h a stable solid-Vapour interface, if the radial temperature gradient inside the crystal was large. The solid-vapour interface was unstable, if the radial temperature gradient inside the crystal was low.