Transparent conducting Sc-codoped AZO film prepared from ZnO:Al-Sc by RF-DC sputtering

Al and Sc-codoped zinc oxide (also expressed as Sc-codoped AZO or ZnO:Al-Sc) films were sputtered on STN glass using RF power sources on ZnO and DC power sources on Al-1.7wt.% Sc alloy. X-ray diffraction (XRD) of the codoped films displayed that they are crystalline and textured at (002) and (103). Examination through transmission electron microscopy (TEM) depicted that these films consists of columnar grains. X-ray photoelectron spectroscopy (XPS) analysis of the films indicated that the O1s comprises O(I), O(II), O(III), and O(IV). The component O(I) centered at 530.00 ± 0.15eV was attributable to Sc₂O₃; the O(III) at 531.25 ± 0.20eV was to the oxygen deficient regions within the matrix of ZnO. The transmittance of visible light (i.e., wavelength in the range from 400 to 800nm) for the film was higher than 80%. The electrical resistivity is lower (1.76 < 2.81Ω-cm), the corrosion-resistance in 3.5% NaCl solution is better for the codoped film in comparison with the usual AZO. Heat treatment of the films (at 200-400°C for 1h) improved the optical transmittance, electrical conductivity, and corrosion-resistance in saline solution.