Display substrates and display devices with reduced electrical resistance are disclosed. One inventive aspect includes a switching device, a first wiring and a second wiring. The switching device includes a first semiconductor layer, first and second gate insulation layers, a source electrode and a drain electrode. The source and drain electrodes are formed to electrically connect, through the first and second gate insulation layers, to the first semiconductor layer. The second wiring is formed on the second gate insulation layer and electrically connected to the first wiring.