ITO/Ag alloy/ITO multilayer structure as an alternative to ITO for display electrodes

Abstract We have developed a Ag alloy for nano‐Ag films used as conductive transparent electrodes. Pure Ag does not readily form stable ultra‐thin films because of agglomeration. The proposed Ag alloy enables the formation of a fine and durable ultra‐thin film by suppression of Ag agglomeration. Nano‐Ag film using the Ag alloy (ITO/Ag alloy/ITO multilayer structure) shows better electrical properties than ITO film, with optical properties equivalent to those of ITO. Furthermore, this structure also shows better flexibility due to the ductility of Ag. The mechanism for inhibiting agglomeration in the Ag alloy is also discussed. The additive element in the Ag alloy suppresses surface diffusion, which is the main factor in Ag agglomeration, by segregation on the film surface. When heat treatment is applied, the additive becomes more segregated and covers the surface and more strongly suppresses the surface diffusion as a result. This is because the Ag alloy film shows high durability against heat. Through this investigation, we confirm that the Ag alloy has a much greater activation energy for agglomeration than pure Ag.