Single crystals were grown by sublimation in closed ampoules of fused silica at temperatures of between 1300 and 1400K. It was observed that the crystals preferentially developed {110} faces. The free corner of three {110} faces appeared to be the preferred formation site of a twin nucleus. Repeated twin formation led to predominant growth in the <111> direction. In the presence of SiS2, {100} and {111} faces appeared near to equilibrium, and twins formed on {111} faces; thus resulting in preferred growth in <112> directions. The observations were explained in terms of an idealized atomic arrangement of growth steps.

In situ observation of twin formation during the growth of ZnSe single crystals from the vapor phase E.Schönherr, M.Freiberg: Journal of Crystal Growth, 1999, 197[3], 455-61