High responsivity and high-speed 1.55 μm infrared photodetector from self-powered graphene/Si heterojunction

A self-powered Gr/Si heterojunction was successfully fabricated by using graphene film as active area. The device exhibits a responsivity approaching 39.5 mAW−1, together with a high-speed response speed up to 5.0 μs to communication wavelength of 1.55 μm. [Display omitted] •A self-powered Gr/Si heterojunciton photodetector was fabricated by using graphene as the active area.•The Gr/Si heterojunciton photodetector shows an excellent rectification behavior and a sensitivity to 1.55 μm IR light.•High responsivity and high speed of the Gr/Si heterojunction were achieved.•The device performance are superior to most of previous graphene-based photodetectors. Graphene has shown great potentials for new-generation photodetectors in view of its outstanding optical and electrical properties, especially its ultra-broad range absorption. Most of graphene(Gr)/Si hybrid two-dimensional(2D)-three-dimensional(3D) photodetectors, which offer a perspective on future application in integrated optoelectronics, are still however enabled the excellent detection on visible light. Herein, we reported a self-powered Gr/Si Schottky heterojunciton with a high sensivity to communication light of 1.55 μm wavelenght by using graphene film as active area. The resultant photodetectors showed a high-speed response speed up to 5.0 μs, togther with a responsivity approaching 39.5 mAW−1, which are comparable with previous graphene-based photodetectors and superior to previous Gr/Si heterojunction. The high-performance of the schottky heterojunction can be ascribed to featuring a built-in field facilitating to separate photocarriers. Combined our results with the methodology of devcie fabrication, can be utilized as pathway for large-area integration of 1.55 μm communication light photodetectors.