Properties And Applications Of Infrared Transparent And Electrically Conductive In2O3 Thin Film

High quality infrared (1-12μ) transparent and electrically conductive thin films based on thermally evaporated In903 have been developed. Optical constants of these films have been obtained by the use or an iteration technique, which involves the formulas for multiple transmition and reflection. The details of the film deposition process and the theoretical foundation leading to its development are discussed in this paper. It has been found that the transparency and conductivity of these films is primarily due to high electron concen-tration and mobility. A multilayer design of a bandpass filter has been developed and implemented on ZnS and ZnSe substrates for the wavelength range of 8 to 12 μp. Typical transmittance of 65 to 80% with a film sheet resistance of 20 to 50 Ω/sq. has been achieved. Such a design is applicable to forward looking infrared (FLIR) systems where a window having both high electromegnetic (RF and microwave) shielding effectiveness and good in-frared transparency are required. The properties of these films lend themselves to many other potential applications.