GROWTH OF CUBIC ZNS, ZNSE AND ZNSXSE1-X SINGLE-CRYSTALS BY IODINE TRANSPORT

High-purity, large ZnSxSe1-x (0 ≤ x ≤ 1) single crystals have been grown by the iodine transport method. The growth conditions for preparing large single crystals without any grain boundaries by avoiding physical contact with the wall of the growth ampoule due to the use of a seed are presented (growth temperature 850°C, iodine concentration of 5 mg/cm3). In particular, the grain size depends strongly upon the temperature difference between the seed crystal and the source powder, ΔT, and on the growth ampoule geometry. Single crystals with dimensions as large as 24 x 14 x 14 mm3 have been prepared with ΔT as low as 7°C using an ampoule with a steep conical tip. The characterization by X-ray diffraction and microscopic observation under polarized light has shown that this technique particularly enables the growth of large, highly perfect cubic ZnS single crystals. The resistivities of all the ZnS crystals annealed in molten Zn show reproducibly low values in the range 1 to 2 Ω cm. © 1979.