A thin film transistor substrate includes an insulating plate; a gate electrode disposed on the insulating plate; a semiconductor layer comprising a metal oxide, wherein the metal oxide has oxygen defects of less than or equal to 3%, and wherein the metal oxide comprises about 0.01 mole/cm3 to about 0.3 mole/cm3 of a 3d transition metal; a gate insulating layer disposed between the gate electrode and the semiconductor layer; and a source electrode and a drain electrode disposed on the semiconductor layer. Also described is a display substrate. The metal oxide has oxygen defects of less than or equal to 3%, and is doped with about 0.01 mole/cm3 to about 0.3 mole/cm3 of 3d transition metal. The metal oxide comprises indium oxide or titanium oxide. The 3d transition metal includes at least one 3d transition metal selected from the group consisting of chromium, cobalt, nickel, iron, manganese, and mixtures thereof.