Photovoltaic high-performance broadband photodetector based on the heterojunction of MoS2/silicon nanopillar arrays

Two-dimensional MoS2 has shown great potential in the photoelectric field because of its excellent optical and electrical properties. However, the performance of MoS2-based planar photodetector is constrained by the short transmission path and limited light absorption capacity of the planar thin layer of MoS2. In this paper, highly sensitive MoS2/silicon nanopillar arrays(Si-NPAs) photodetector by coating the surface of silicon nanotrap light array with MoS2. The interaction between light waves and silicon nanopillars and MoS2 is significantly enhanced by the Fabry-Pérot-enhanced Mie resonance between pillars as well as the multiple reflection . In the meantime, a Van der Waals heterojunction is constructed between the MoS2 and Si-NPAs coated across a large area. This is beneficial to address the poor performance of traditional two-dimensional photodetectors in light absorption and prevent the surface recombination of silicon-based photodetectors. According to the research results,the detector has 4.15×102 excellent rectification characteristics and 1.93×103 high switch ratio, and the photovoltaic effect is significant. The average external quantum efficiency of MoS2/Si-NPAs photodetector is 61.2% in the visible and near infrared bands , which is twice that of MoS2/planar silicon photodetector. At 850 nm, the responsiveness of the MoS2/Si NPAs photodetector is 0.48 A/W. the detection rate reaches 1.058×1012cm·Hz 1/2 W-1, which is 10.7 times higher than that of MoS2/planar silicon photodetector. To sum up, this study contributes a fresh idea to the design and application of high-performance devices.