Crystals of Hg1-xCdxTe, with x approximately equal to 0.2, were grown (using the travelling-heater method) in the [111]A or [¯1¯1¯1]B directions by using oriented CdTe seeds. It was noted that lamellar and double-position twins were sometimes formed during the growth of these crystals. Lamellar twinning occurred during layer-by-layer growth, and was due to high stresses which arose from high thermal gradients. Double-position twins developed under conditions of multiply nucleated growth. This type of growth occurred towards the end of the growth run, due to the concave shape of the growth interface at that stage. In the case of crystals which had been grown in the [111]A direction, lamellar twins (with the orientation, [¯5¯1¯1]B) constantly grew at the expense of the original [111]A-oriented grain. On the other hand, growth in the [111]B direction suppressed growth of the lamellar twin domain. The annihilation was due to arrays of small interstitial ions. Ingots which were grown in the [¯1¯1¯1]B direction were almost entirely monocrystalline, with a growth axis of <111> type. Photodiodes and capacitors which were prepared on the (111)A plane were markedly superior to those which were prepared on the lamellar twin plane, (¯5¯1¯1)B. This difference was attributed to a much higher fixed charge, and larger fast surface state density, in the case of the (¯5¯1¯1)B plane. These effects were explained in terms of the lattice structures in the {111} and {511} planes and their possible effect upon surface reactivity.

E.Weiss, E.Kedar, N.Mainzer: Journal of Crystal Growth, 1993, 132[1,2], 191-9