Surface-TexTure evoluTion of DifferenT chemical-vapor–DepoSiTeD Zinc SulfiDe flaTS

LLE Review, Volume 142 110 Introduction Zinc sulfide (ZnS) is an infrared (IR) optical material widely used for applications such as IR windows, domes, and optical lenses.1 It is industrially produced by the chemical-vapor–deposition (CVD) technique to reach a dense, milky yellow–orange color, with +70% transmission in the mid-long-wave IR region.1 Its inner structure consists of cone-like structures that grow larger as deposition takes place, up to a thickness of a few centimeters.2,3 These cone-like structures manifest on the top of the deposited surface as “pebbles”2 or “hillocks”4 and are often called “alligator skin.”5