High quality transparent heat reflectors of reactively evaporated indium tin oxide

Abstract

Transparent and heat reflecting indium tin oxide films were prepared by electron beam evaporation of In2O3+9 mol.% SnO2 onto glass in an oxygen atmosphere of ∼5×10−4 Torr. Visible light absorption less than 2%, thermal infrared reflectance exceeding 90%, and a dc resistivity of ∼3×10−4 Ω cm were obtained for 0.3-μm-thick films deposited on a substrate at 300 °C. Similar properties could be achieved with substrate temperatures as low as 150 °C. By antireflection coating the films with an MgF2 layer, the visible transmittance exceeded the transmittance of the uncoated glass while the infrared reflectance was practically unchanged.