Methods are disclosed for making semiconductor windows which are transparent to light in the infrared range which have good electrical conductivity and are formed of a substrate material (11) having a semiconductor coating (14) having a dopant included therein. The coating is diffused, grown or deposited on one surface of the substrate and is controlled to obtain both low electrical resistivity and high infrared transmissivity. The coating can be formed of the same material as the substrate or can be a different material. Windows having particular thermal properties are formed utilizing zinc selenide and zinc sulfide as the substrate.