Fig. 1

Device design and fabrication. a A Si–Gr–Ge transistor is built by directly stacking a Si membrane, single-layer graphene and a Ge substrate. b Optical image of a Si–Gr–Ge transistor (scale bar: 20 μm). c SEM image of a Si membrane on graphene (scale bar: 4 μm). d Illustration of the cross-section of the transistor. e Illustration of the basic operating principle of the transistor