Crystal Growth


II-VI Incorporated was founded in 1971 to supply better materials to infrared optics producers. Initially starting with cadmium telluride, II-VI gravitated to producing zinc selenide and zinc sulfide during the 1980s. II-VI’s vertical integration, from materials growth through precision optics manufacturing, positions the company as the leader in CO2 laser optics. II-VI produces zinc selenide and zinc sulfide by using a process called chemical vapor deposition (CVD). In specially designed furnaces, zinc vapors are reacted with hydrogen selenide or hydrogen sulfide gas to produce zinc selenide or zinc sulfide, respectively. The reaction deposits the material in crystalline form on the deposition plates. Following the removal from the furnace, material is cut, polished, and tested for optical quality. The material is then used to produce optics or sold as sheet stock or optic blanks. Products Offered II-VI Infrared produces the following infrared materials (pictured below):

  • Zinc selenide
  • Zinc sulfide regular grade
  • Zinc sulfide MultiSpectral grade

Zinc sulfide MultiSpectral grade is regular grade material treated after growth using a hot isostatic press process to remove growth voids and defects. The result is a product that is useful within the infrared and visible spectrums. II-VI offers a wide variety of standard sizes and thicknesses for sheet stock and optic blanks, and produces custom sizes and thicknesses upon request.


After chemical vapor deposition, zinc selenide material undergoes the blanking and grinding process to remove what II-VI calls “alligator skin.”

II-VI Infrared’s three materials fabricated at our Saxonburg plant, from left to right: zinc sulfide, zinc sulfide MultiSpectral, and zinc selenide.