A thin-film transistor (TFT) array substrate includes: a driving TFT provided on a substrate; and a switching TFT provided on the substrate and including: a switching semiconductor layer including a switching channel region, a switching source region, and a switching drain region; and a switching source electrode and a switching drain electrode contacting the switching semiconductor layer. The switching source electrode includes a source contact portion contacting the switching source region, and the switching drain electrode includes a drain contact portion contacting the switching drain region. The source contact portion is doped with ions that are different from ions of the switching source region and the drain contact portion is doped with ions that are different from ions of the switching drain region.