The present invention relates to a semiconductor structure. The semiconductor structure comprises a semiconductor layer, at least one metallic carbon nanotube, and at least one graphene layer. The semiconductor layer defines a first surface and a second surface opposite to the first surface. The at least one metallic carbon nanotube is located on the first surface of the semiconductor layer. The at least one graphene layer is located on the second surface of the semiconductor layer. The at least one metallic carbon nanotube, the semiconductor layer and the at least one graphene layer are stacked with each other to form at least one three-layered stereoscopic structure. The present invention also relates a semiconductor device, and a photodetector.