A two-dimensional semiconductor which is configured for contacting two metals includes a first semiconductor layer and a plurality of second semiconductor layers. The first semiconductor layer includes a channel region and two metal contacting regions. The two metal contacting regions are connected to two sides of the channel region, respectively. The second semiconductor layers and the two metal contacting regions of the first semiconductor layer form a plurality of heterojunctions having type-II band alignment, respectively, wherein the heterojunctions are arranged and spaced from each other. Therefore, contact resistance can be reduced. |