Horizontal unseeded vapor growth of Iv-Vi compounds and alloys

Large, high-quality crystals of various Pb-salt compounds and alloys have been grown from the vapor by a horizontal, unseeded, closed-tube method. The optimum growth conditions have been experimentally determined. The crystalline imperfections and electrical properties of the crystals were examined. In a series of growth experiments on PbTe, the source materials were prepared by adding small quantities of Pb to much larger quantities of zone-melted PbTe. This method makes it possible to control the source and as-grown crystal compositions for excess Pb or Te concentrations in the 10¹⁸/cm³ range. From the results of these experiments it was found that the composition of zone-melted PbTe (i. e., the maximum-melting point composition of PbTe) corresponds to a hole concentration of approximately 1 x l0¹⁹/cm³. This work was sponsored by the Department of the Air Force.