A solar cell includes a substrate of a first conductive type; an emitter part of a second conductive type positioned at a front surface of the substrate; a first silicon thin film layer positioned on the emitter part and including amorphous silicon containing impurities of the second type that are doped therein; a first transparent conductive layer positioned on the first silicon thin film layer and electrically connected with the emitter part; a first electrode positioned on the first transparent conductive layer and electrically connected with the first transparent conductive layer; and a second electrode positioned on a back surface of the substrate. For example, the first silicon thin film layer includes N+-a-Si:H or N+-a-SiC:H.