▎ 摘　　要

Due to its atomically ultrathin morphology and superior optoelectronic properties, graphene has been broadly studied and utilized in phototransistors, photoconductors, or heterojunction nanostructures. However, in practical devices, the disadvantages of graphene should be concerned for its high dark current, very low on/off ratio, and high-priced fabrication cost. We report the photodetecting of the graphene/ insulator/silicon heterojunction. The insulator layer is optimized to achieve balanced optoelectronic properties in terms of an Iph/Idark ratio of 4.17 x 10(3), a responsivity of 35 mA W-1, and a detectivity of 6.39 x 10(10) Jones at a wavelength of 658 nm, with low operating voltage and static power dissipation (0.84 nW). Besides, response speed and degradation in the environment are tested. The mechanisms are revealed and analyzed by I-V measurements. Published under license by AIP Publishing.