A NOVEL METHOD OF CRYSTAL-GROWTH BY PHYSICAL VAPOR TRANSPORT AND ITS APPLICATION TO CDTE

A novel method of in-situ "nucleation" and growth by physical vapour transport has been developed and applied to CdTe. The main feature of this method is the technique for formation of a perfect seed in the first stage of the crystal growth procedure. In this technique, due to imposing thermal conditions, the source material takes the form of a cone. The monocrystalline tip of this cone moves towards the surface of a crystal holder, adheres to it and then separates from the remaining part of the source. This single crystal serves subsequently as a seed for the bulk physical vapour transport growth process. The crystal grows inside a silica glass ampoule without wall contact. Large, high-quality single crystals of CdTe up to 8 cm3 of both p-type and n-type have been grown using this method. The etch pit density on the exposed {111} crystal faces was found to be as low as 2 x 10(3) cm-2. The half-maximum width of the rocking curve measured on the exposed {111} surfaces was between 24 and 100 arc sec. The resistivity and optical absorption of the crystals are also reported.