ITO/Ag/ITO multilayer films for the application of a very low resistance transparent electrode

Abstract

Multilayer transparent electrodes, having a much lower electrical resistance than the widely used transparent conducting oxide electrodes, were prepared by using magnetron sputtering. The multilayer structure consisted of three layers, tin-doped indium oxide (ITO)/Ag/ITO. Because only Ag deposits with a thickness larger than 14 nm form a continuous film, the optimum thickness of Ag thin films was determined to be 14 nm for high optical transmittance and good electrical conductivity. With about 55–60 nm thick ITO films, the multilayer showed a high optical transmittance in the visible range of the spectrum and had color neutrality. The electrical and optical properties of the ITO/Ag/ITO multilayer were changed mainly by Ag film properties, which were affected by the deposition process of the upper layer. A high quality transparent electrode, having a resistance as low as 4 Ω/□ and a high optical transmittance of 90% at 550 nm, was obtained and could be reproduced by controlling the preparation process parameters properly. It could satisfy the requirement for the SVGA mode STN-LCD.