Abstract: A manufacturing method of a solar cell includes the following steps, providing a substrate, which includes a first conductivity type semi-conductor layer and a second conductivity type semi-conductor layer. The conductivity type of the first conductivity type semi-conductor layer is opposite to the conductivity type of the second conductivity type semi-conductor layer. A graphene oxide layer is formed on the substrate and the graphene oxide layer contacts with the second conductivity type semi-conductor layer. A first electrode and a second electrode are formed on the substrate. The first electrode contacts with the first conductivity type semi-conductor layer, and the second electrode contacts with the second conductivity type semi-conductor layer.

Abstract: A thin-film solar cell having a hetero-junction of semiconductor and the fabrication method thereof are provided. Instead of the conventional hetero-junction of III-V semiconductor or homo-structure of IV semiconductor, the thin-film solar cell according to the present invention adopts a novel hetero-junction structure of IV semiconductor to improve the cell efficiency thereof. By adjusting the amount of layer sequences and the thickness of the hetero-junction structure, the cell efficiency of the thin-film solar cell according to the present invention is also optimized.

Abstract: A photodetector is provided. The photodetector includes a base piece; a germanium layer mounted on the base piece and including a first area and a second area; a first metal electrode mounted on the first area; an insulation layer mounted on the second area; and a second metal electrode mounted on the insulation layer.