Growth of Twin Free AgGaS2 Single Crystals Using a Modified Gradient Freezing Technique

Single crystals of AgGaS₂ were grown by a modified gradient freezing technique. Seeded melt growth was performed using seeds with their [O i l] direction parallel to the ampoule axis. In order to reduce the number of shallow hemispherical crater on the surface of the crystals the feed material was superheated 40 K above the melting point of AgGaS₂ (T_melt = 1268 K). The grown crystals were up to 55 mm in length and 12 mm in diameter. The transparency in the visible of the crystals was comparable to those grown by the conventional Bridgman method.