Title: The relative occurrence of hexagonal and rhombohedral structures in ZnS single crystals
Abstract: Besides the three-layered cubic (3C) and two-layered hexagonal (2H) forms, ZnS crystallizes into a number of hexagonal and rhombohedral polytypes. The polytypes of zinc sulphide are considered to generate during the 2H–3C structural transformation around axial screw dislocations with various Burgers vector strengths. By consideration of energies involved in producing axial screw dislocations, it has been pointed out that the growth of rhombohedral polytypes alone is favoured at the limit of higher unit-cell height and the growth of both the hexagonal and rhombohedral polytypes at the limit of lower height. The possibility of the relative occurrence of the hexagonal and rhombohedral polytypes, with the same unit-cell heights but with different stacking modes of ZnS double layers, has also been discussed.