Crystal growth part ii: the growth of zinc sulphide crystals

Abstract

This report is an in-depth study of problems encountered in the growth of synthetic single crystals of zinc sulphide. The four growth procedures explored were: Chemical Vapour Transport, Vapour Transport (Sublimation), Flux Growth, and Hydrothermal Growth. The prime goal of growing centimetre-sized crystals of sphalerite was achieved by both the chemical vapour transport method, using either HCI or I 2 as the carrier, and by the vapour transport method. A few millimetre-sized single crystals of wurtzite have been obtained by the vapour transport method. The report includes sections dealing with the purification of zinc sulphide powders, the doping of zinc sulphide crystals with either Al or Fe, various analyses of powder and crystalline samples, and also some characterizations of the single crystals. The yellow-green colouration in some synthetic ZnS crystals has been found to be caused by departure of the ZnS ratio from the required 1:1 stoichiometry.