Thin film transistor substrate having two different types of thin film transistors on the same substrate and display using the same

The present disclosure relates to a thin film transistor substrate having two different types of thin film transistors on the same substrate and a display using the same. A disclosed display device may include a substrate, a first thin film transistor including a first semiconductor layer having a polycrystalline semiconductor material on the substrate, and a second thin film transistor including a second semiconductor layer including an oxide semiconductor material on the substrate. Both the first semiconductor layer and the second semiconductor layer may be disposed directly on a same underlying layer.