FAST VAPOR GROWTH OF CADMIUM TELLURIDE SINGLE-CRYSTALS

Cadmium telluride single crystals were grown at growth rates of 35 mm per day by the physical vapor transport (PVT) method under high temper ature gradient conditions. This is believed to be the highest PVT grow th rate of CdTe reported to date. Lamellar twins are the only ones pre sent in the CdTe crystals grown under optimal conditions in this work. At growth rates up to 15 mm per day, the crystals have a dislocation density of approximately 10(4) cm-2. The etch pit density increases to approximately 10(5) cm-2 with an increase of the growth rate up to 35 mm per day. Based on a uniform thermal field and high interface stabi lity, which are established by large temperature gradients up to 40-de grees-C/cm at the growth interface, spurious nucleation and lateral tw ins were effectively eliminated, and the density of the lamellar twins remained low at crystal growth rates up to 35 mm per day. The major c ontributions of the high temperature gradients to the single crystalli ne growth and the apparent origin of polycrystalline grains are also d iscussed in this paper.