MASS-TRANSPORT AND CRYSTAL-GROWTH OF CADMIUM TELLURIDE BY PVT

Systematic mass transport rate studies of CdTe in closed ampoules demonstrate the influence of source material synthesis and pretreatment on the physical vapor transport properties of this material. Minute deviations from the nominal stoichiometric composition of CdTe reduce the mass flux by several orders of magnitude. These observations could explain the large discrepancies in vapor transport and crystal growth rates of CdTe reported in the literature. Crystal growth experiments show that the unseeded vapor growth of CdTe by this technique yields crystal boules with large single crystalline grains. The results of x-ray diffraction and of chemical etching studies reveal that the single crystallinity of the grains is comparable to that of of CdTe grown by other techniques. The combined results are promising for the further refinement of the vapor transport and crystal growth of CdTe.