A thin-film transistor substrate includes a semiconductor layer disposed on a substrate, a gate insulating layer disposed on the semiconductor layer, a first electrode that at least partly overlaps the semiconductor layer, wherein the gate insulating layer is disposed between the first electrode and the semiconductor layer, a plurality of thin-film layers disposed on the first electrode, and a second electrode that at least partly overlaps the first electrode, wherein the plurality of thin-film layers are disposed between the second electrode and the first electrode, wherein at least one of the plurality of thin-film layers includes amorphous silicon.