Electroluminescence in Disordered Zinc Sulphide

Abstract

IN recent times a detailed study has been made of the structure of zinc sulphide crystals¹, and of the solid-state properties, particularly electroluminescence², of this compound. of the many factors which may influence the electrical and optical properties of zinc sulphide, little attention has so far been paid to the effect of the modifications which can occur in the crystal structure. In addition to the well-known cubic (sphalerite) and hexagonal (wurtzite) forms, single crystals of zinc sulphide can also be obtained with a one-dimensional stacking disorder of the hexagonal (0001) planes³. This disorder may exhibit a periodic arrangement resulting in the formation of polytypes¹. Although no experimental work seems to have been published linking electroluminescence with disorder, Schneer⁴ has, from theoretical considerations, suggested that there may be some connexion; in addition, the electroluminescent properties of some zinc sulphide phosphors have been tentatively ascribed to a partial transformation from hexagonal to cubic⁵.