ABSTRACT
This chapter addresses the fundamental processes that lead to light emission in Zinc sulphide (ZnS) phosphors. It examines the various device structures and fundamental physical mechanisms that lead to electroluminescence in ZnS phosphors. ZnS is widely used in all types of high-field electroluminescent devices. The electrons of isolated luminescent ions arrange themselves in a manner such that the total energy of the ion is minimized. The outer energy levels of ions, bound together to form a solid, are significantly influenced by their surroundings. The electric potential at the interface brings into coincidence the energy of the ZnS conduction band states with the metal Fermi level, at which point carrier injection from the cathodic metal into the ZnS conduction band can occur by tunnelling.
