Thin films of Al, Sc-co-doped ZnO varying with Sc-contents were sputtered on the glass substrate. X-ray diffraction (XRD) of the films revealed wurtzite crystals that were confirmed through the analysis of high resolution transmission electron microscopy (HRTEM). With increasing the Sc-content from 0 to 2.37 wt.% in the films, the optical energy band gap (Eg) was estimated to decrease from 3.25 to 3.20 eV, and the electrical resistivity (Omega cm) decreased from 3.8 x 10(-3) to 1.3 x 10(-3). The decrease in resistivity may be ascribed to electrons tunneling through the horizontal stacking faults induced by Sc-dopants in the films. Published by Elsevier B.V.