An asymmetry thin-film transistor includes a substrate, a semiconductor layer positioned on the substrate, and a gate positioned on the substrate. The semiconductor layer has a channel region, a single lightly doped region and a first heavily doped region positioned at a side of the channel region, and a second heavily doped region positioned at the other side of the channel region. The semiconductor layer has a central line extending through the semiconductor layer and the substrate, the first heavily doped region and the second heavily doped region have equal lengths and are symmetric with respect to the central line of the semiconductor layer, and the gate is asymmetric with respect to the central line of the semiconductor layer. There is no lightly doped region in between the channel region and the second heavily doped region.