Effect of added metallic elements in Ag alloys on the durability against heat and humidity of indium zinc oxide/Ag alloy/indium zinc oxide transparent conductive multilayer system

Abstract

We studied the effects of added metallic elements in the Ag alloy layers of the indium zinc oxide (IZO)/Ag alloy/IZO transparent conductive multilayer system on the optical and electrical properties of the multilayer The correlation between the thickness of the Ag alloy layers and the optical and electrical properties of the multilayer was also investigated The transmittance and sheet resistance were estimated from the optical constants and specific resistivities of Ag alloy and IZO and then compared with the experimentally measured values A high transmittance of 95 3% at a 550 nm wavelength and a low sheet resistance of 4 3 Omega/square were achieved from the IZO (40 nm)/Ag (15 nm)/IZO (40 nm) multilayer The effect of added metallic elements in the Ag alloy layers of the multilayer on the durability against heat and humidity was also investigated The durability against heat was improved by the added metallic elements in the Ag alloy layers of the IZO/Ag/IZO multilayer system When Ag film was heat treated agglomeration occurred owing to the surface diffusion of Ag atoms The added metallic elements such as Pd Cu and Au increased the onset temperature and the activation energy for agglomeration The optical and electrical properties of the IZO/Ag/IZO multilayer markedly deteriorated after the humidity test at 85 degrees C-85% relative humidity (RH) in air The degradation of Ag alloy layer was due to the combined effect of heat water vapor and sulfur in air However the deterioration did not occur in the IZO/Ag alloy/IZO multilayer with a AgAu layer after the humidity test The IZO/Ag alloy/IZO multilayer with the AgAu layer containing 10 wt % Au especially exhibited superior characteristics with a high transmittance of 93 5% at a 550 nm wavelength and a low sheet resistance of 6 3 Omega/square after the humidity test at 85 degrees C-85% RH in air for 720 h (C) 2010 The Japan Society of Applied Physics