Highly stable and sensitive photoelectrochemical photodetectors based on a ZnO nanorod/monolayer MoS2 nanosheets heterostructure

Construction of type-II heterostructures between metal oxide nanorod arrays and narrow band gap semiconductors is a proven strategy for enlarging the surface area, shortening the diffusion length, broadening the light harvesting ability, and facilitating carrier transport, which are of great significance for photoelectrochemical (PEC) photodetectors. A ZnO/MoS2 heterostructure was designed and fabricated via a facile hydrothermal process accompanied by chemical vapor deposition method. The ZnO nanorod/monolayer MoS2 nanosheet heterostructure was revealed with scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. These heterojunction-based PEC photodetectors showed higher photoresponsivity (4.2 mA/W) than those of ZnO (-0.9 mA/W) and MoS2 photodetectors (-0.007 mA/W) due to its fast interfacial charge transfer and efficient light capture. Furthermore, the ZnO/MoS2 heterostructural photodetectors exhibited a maximum photoresponsivity of approximately 5.0 mA/W at 420 nm and long-term stability even over 6 h. Our work paves the way to rationally designed heterostructures for high-performance and stable photodetectors and beyond.