Method of manufacture of optically transparent electrically conductive semiconductor windows

A method for making a conductive infrared transparent window comprising the steps of:

• providing an infrared transparent substrate of germanium,
• forming an added layer of infrared transparent germanium from 1-50 microns thick at one surface of said substrate by epitaxially growing a coating thereon,
• co-depositing an n type impurity dopant selected from the group of phosphorus, arsenic, and antimony while growing said coating for rendering the layer electrically conductive with a sheet resistance of less than 100 ohms per square to render said layer conductive, while
• maintaining a sufficient mobility to retain the infrared transparency of said layer at a value greater than about 55% of optical transmittance over the infrared range, said layer becoming, upon doping, a distinctly different material from said substrate which is left undoped,
• said layer being formed as a crystalline layer with a low density of micro-structural defects to thereby essentially maintain the infrared transparency thereof.