Single crystal growth of SrIn2VI4 (VI=S,Se) compounds solidifying through supercooling

Abstract The IIa–III 2 –VI 4 (IIa=Ca,Sr, III=Ga,In, VI=S,Se) compounds generally have high melting points more than 1100 °C, and some of them, e.g., SrIn 2 VI 4 (VI=S,Se) prefer freezing with supercooling, which makes their crystal growth very difficult. Here, we have adopted a carbon crucible sealed in a quartz ampoule to escape from both the supercooling and the reactivity near the melting point. We have devised the shape of a crucible by preparing a small capillary followed by a bigger hollow pipe for obtaining a large single crystal. A compound is filled in the hole of a crucible by setting the thin part down. It is first heated above the meting point to melt and then cooled down below the supercooling point, where it is solidified. It is again heated to melt but this time keeping the temperature of the small bottom part of a capillary a little below the melting point. Then the melt is slowly cooled down. The nucleation is started from the polycrystalline remainder near the bottom, resulting in a seed crystal in the rest of the thin part as temperature lowers. With the help of the seed, a single crystal continues to grow in a bigger hollow-pipe part of a crucible. Single crystals of SrIn 2 S 4 and SrIn 2 Se 4 are grown by this method, and their optical absorption is measured.