Hybrid structure of PbS QDs and vertically-few-layer MoS nanosheets array for broadband photodetector.

A novel three-dimensional (3D) vertically-few-layer MoS (V-MoS) nanosheets- zero-dimensional PbS quantum dots (QDs) hybrid structure based broadband photodetector was fabricated, and its photoelectric performance was investigated in detail. We synthesized the V-MoS nanosheets by chemical vapor deposition, using the TiO layer as the induced layer, and proposed a possible growth mechanism. The use of the TiO induction layer successfully changed the growth direction of MoS from parallel to vertical. The prepared V-MoS nanosheets have a large specific surface area, abundantly exposed edges and excellent light absorption capacity. The V-MoS nanosheets detector was then fabricated and investigated, which exhibits a high sensitivity for 635 nm light, a fast response time and an excellent photoelectric response. The V-MoS nanosheets with a height of approximately 1 μm successfully broke the light absorption limit caused by the atomic thickness. Finally, we fabricated the PbS QDs/V-MoS nanosheets hybrid detector and demonstrated their potential for high-performance broadband photodetectors. The response wavelength of the hybrid detector extends from the visible band to the near-infrared band. The responsivity of the hybrid detector reaches 1.46 A W under 1450 nm illumination. The combination of 3D MoS nanosheets and QDs further improves the performance of MoS-based photodetector devices. We believe that the proposed zero-dimensional QDs and 3D vertical nanosheets hybrid structure broadband photodetector provides a promising way for the next-generation optoelectronic devices.