Chemical vapor transport and crystal growth of the Hg/sub 0.8/Cd/sub 0.2/Te system, crystal morphology and homogeneity

Mass transport rate studies of the system Hg/sub 1-x/Cd/sub x/Te-iodine (with x = 0.2 for the source material) are performed in the temperature gradient 5900 → 535 0C as a function of transport agent pressure and for different orientations of the density gradient relative to the gravity vector. The combined results reveal that convection, even when not sufficient to increase the diffusive mass transport rates appreciably at low pressures, affects the surface morphology and compositional homogeneity of crystals. Under vertical, stabilizing conditions, the crystallographic and chemical homogeneity of crystals is distinctly improved relative to those obtained for the horizontal orientation of the transport ampoule. These result suggest that elimination of convection (micro-g environment) may yield a further improvement of crystals. (author)