Preferred [1 1 1] growth of ZnSe crystals from the vapor due to repeated twinning

Abstract ZnSe crystals have been grown by sublimation at 1340 K. The crystals develop preferably {1 1 0} faces. When three adjacent faces, e.g. (1 1 0) H , (1 0 1) H and (0 1 1) H form a corner an ortho-twin is frequently generated at that particular tip. The (1 1 1) twinning plane provides the initially flat twin with steps over the {1 1 0} twin side faces so that again a three-sided pyramid appears with a decreasing (1 1 1) top face. In contrast to the usual twin-induced 〈1 1 2〉 growth, the repeated twinning on the pyramid vertex leads to a preferred [1 1 1] growth.