A display device is provided. A thin film transistor structure of the display device includes a substrate, a gate electrode disposed on the substrate, a gate insulation layer disposed on the substrate and the gate electrode, a channel layer on the gate insulation layer and corresponding to the gate electrode, and a source electrode and a drain electrode contacting two sides of the channel layer, respectively, and extending onto the gate insulation layer. The channel layer includes a first metal oxide semiconductor layer, which includes (1) tin and (2) at least one of gallium, hafnium, and aluminum.