Effect of anatase TiO₂ doping power on electrical, optical and structural properties of multicomponent TiO₂-doped ITO electrodes

We report on the effects of TiO₂ doping power on the characteristics of multicomponent TiO₂-ITO (TITO) electrodes prepared by a multi-target sputtering system with tilted cathode guns. Both as-deposited and annealed TITO electrodes showed linearly increased sheet resistance and resistivity with increasing TiO₂ doping power. However, the TITO electrodes exhibited a fairly high optical transmittance regardless of the TiO₂ doping power due to the high transparency of the TiO₂. Although the annealed TITO showed much lower sheet resistance and resistivity relative to the as-deposited samples, the electrical properties of the annealed samples exhibited similar dependence on the TiO₂ power to the as-deposited samples. In addition, it was found that doping of an anatase TiO₂ in the ITO electrode prevented the preferred (222) orientation of the TITO electrodes. Although the TITO electrode showed higher sheet resistance and resistivity than that of the pure ITO electrode, it offers a very smooth surface and usage of a low-cost Ti element. It is thus considered a promising multicomponent transparent conducting electrode for cost-efficient flat panel displays and photovoltatics.