p-type silicon (p-Si)/macro-assembled graphene nanofilm (nMAG)/n-type silicon (n-Si) heterojunction is utilized to fabricate near-infrared photodetector. Dual built-in electric fields were established in the same direction at the p-Si/nMAG and nMAG/n-Si heterojunctions, providing an enhanced electron-hole separation ability. The p-Si/nMAG/n-Si device has realized responsivities of 90 mA/W and 45 mA/W under 900 nm and 1064 nm illumination at room temperature and corresponding external quantum efficiency (EQE) of 11.8% and 5.2%, respectively, which is 30% and 45% higher than that of the single-junction nMAG/n-Si device. In this work, we applied two-dimensional (2D) carbon materials combined with monocrystalline silicon to explore complementary metal-oxide-semiconductor (CMOS) process-compatible device fabrication techniques, which paves the way to develop low-cost and large-scale near-infrared carbon-based photodetectors.