Crystalline perfection of melt-grown CdTe

Single crystals of CdTe have been grown by the vertical gradient freeze method using both spontaneous nucleation and seeding in the [111] direction. It is shown that almost single grain 50x40 mm crystals containing no twins can be obtained. The interface shapes have been analyzed by the electron microprobe profiling of Zn distribution in CdZnTe crystals and found nearly planar during the major part of growth. The [111] seeded crystals appear to be of clearly superior crystalline perfection compared to the unseeded ones. The difference in quality of the two types of crystals is related to higher thermomechanical stresses imposed on the solidified material when the (111) crystallographic plane is not parallel to the growth interface, as it is in the case of the unseeded grown crystals.