Preparation of GZO/Pt/GZO Multi-Layered Transparent Electrodes and Their Application to Touch Sensor Devices

We have proposed, prepared, and characterized Pt-inserted Ga-doped ZnO (GZO) transparent electrodes of GZO/Pt/GZO (GPG) multilayers on glass and flexible plastic substrates. Pt-inserted GZO electrodes showed remarkably decreased resistivity, even though the thickness of the Pt layer was only a few nm. However, the optical transmittance of the GPG electrodes was degraded with increasing thickness of the Pt layer. The structural, optical, and electrical properties of GZO film and GPG multilayered transparent electrodes on glass substrates were largely affected by post- annealing conditions such as the ambient and temperature. Post-annealing in a N2 ambient was the most effective treatment for achieving high optical transmittance and low electrical resistivity of the GZO films and GPG structure. Good optical transmittance of 78% and electrical resistivity of 3.5 x 10(-3) Ω·cm of the GZO electrode were obtained for the 4-nm-thick Pt insertion layer and post-annealing at 400 °C. In addition, touch sensor devices were fabricated by using GPG structures and flexible plastic substrates. The touch sensor devices exhibited a capacitance ratio of 1.4 between the two states before and after fingertip touching.