A thin-film transistor includes a substrate, a gate electrode formed over the substrate, a gate insulating layer formed over the gate electrode and the substrate, an oxide semiconductor layer formed over the gate insulating layer and comprising a source section and a drain section, a first electrode formed over the substrate and electrically connected to the source section, and a second electrode formed over the substrate and electrically connected to the drain section. The thin-film transistor further includes a first barrier layer disposed between the oxide semiconductor layer and the first electrode, a second barrier layer disposed between the first barrier layer and the first electrode, and the first electrode being electrically connected to the oxide semiconductor layer via the first barrier layer and the second barrier layer.