The hardness of zinc sulfide is increased by adding selective elements within a specified range to the crystal lattice of the zinc sulfide. The increased hardness over conventional zinc sulfide does not substantially compromise the optical properties of the zinc sulfide. The zinc sulfide may be used as a protective coating for windows and domes.

A method is directed to increasing the hardness of zinc sulfide. The hardness of zinc sulfide is increased by adding selective elements within a specified range to the crystal lattice of the zinc sulfide. The increased hardness over conventional zinc sulfide does not substantially compromise the optical properties of the zinc sulfide. The zinc sulfide may be used as a protective coating for windows and domes.

A method of coating a substrate with zinc oxysulphate (ZnO.sub.(1-x)S.sub.x, where 0x1) by atmospheric pressure chemical vapour deposition is disclosed. Various precursors offering sources of zinc, oxygen and sulphur are provided.

This disclosure relates to use of group 4 element codoping in a phosphor layer of activator-doped zinc sulfide of a display element, a display element, and a method for manufacturing a display element. The display element (100) comprises a first insulator layer (111), a second insulator layer (112), and a first phosphor layer (121) of activator-group 4 element codoped zinc sulfide between the first insulator layer (111) and the second insulator layer (112). The first phosphor layer (121) has an average atomic percentage of group 4 elements of at least 0.01 atomic percent.

The hardness of zinc sulfide is increased by adding selective elements within a specified range to the crystal lattice of the zinc sulfide. The increased hardness over conventional zinc sulfide does not substantially compromise the optical properties of the zinc sulfide. The zinc sulfide may be used as a protective coating for windows and domes.

The hardness of zinc sulfide is increased by adding selective elements within a specified range to the crystal lattice of the zinc sulfide. The increased hardness over conventional zinc sulfide does not substantially compromise the optical properties of the zinc sulfide. The zinc sulfide may be used as a protective coating for windows and domes.

GaAs IR window slabs having largest dimensions that are greater than 8 inches, and preferably greater than 12 inches, are grown using the Horizontal Gradient Freeze (HGF) method. Heat extraction is simplified by using a shallow horizontal boat that is only slightly deeper than the desired window thickness, thereby enabling growth of large slabs while also minimizing material waste and fabrication cost as compared to slicing and shaping thick plates from large, melt-grown boules. Single crystal seeds can be used to optimize the final orientation of the slabs and minimize secondary nucleation, thereby maximizing yield. A conductive doped GaAs layer can be applied to the IR window slab to provide EMI shielding. The temperature gradient during HGF can be between 1 C./cm and 3 C./cm, and the directional solidification can be at a rate of between 0.25 mm/h and 2.5 mm/h.