Hybrid structure of PbS QDs and vertically-few-layer MoS2 nanosheets array for broadband photodetector

Abstract

A novel three-dimensional (3D) vertically-few-layer MoS₂ (V-MoS₂) 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-MoS₂ nanosheets by chemical vapor deposition, using the TiO₂ layer as the induced layer, and proposed a possible growth mechanism. The use of the TiO₂ induction layer successfully changed the growth direction of MoS₂ from parallel to vertical. The prepared V-MoS₂ nanosheets have a large specific surface area, abundantly exposed edges and excellent light absorption capacity. The V-MoS₂ 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-MoS₂ 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-MoS₂ 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^-1 under 1450 nm illumination. The combination of 3D MoS₂ nanosheets and QDs further improves the performance of MoS₂-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.