Structural, electrical and bending properties of transparent conductive Ga-doped ZnO films on polymer substrates

We investigated the characteristics of highly transparent conductive Ga-doped ZnO (GZO) polycrystalline films of 100 nm thickness deposited on glass and polymer substrates. GZO films were deposited by ion plating with dc-arc discharge. We developed multiple-deposition method to obtain various deposition process temperatures lower than 100 °C. Cross-sectional SEM images show that all the GZO films have columnar structure. Analysis of data obtained by XRD measurements shows that all the GZO films with wurtzite structure exhibit highly (002) orientation perpendicular to the substrate. The resistivity of the GZO films deposited on polyester and glass substrates were 5.0 × 10-4 Ω · cm. The mechanical bending properties of the GZO films were investigated by comparing the sheet resistance determined before and after a bending test with various bending diameters. For the bending diameter of more than 30 mm, all the GZO films exhibited excellent bending properties with no change in sheet resistance. For the bending diameter of less than 20 mm, we found the sheet resistance affected by the bending. We demonstrated that our multiple-deposition method to achieve different controllable polyester substrate temperatures is highly suitable for improving the bending properties of GZO films.