Abstract:
Molybdenum disulfde (MoS2), a typical 2D metal dichalcogenide (2DMD), has exhibited tremendous potential in optoelectronic device applications, especially in photodetection. However, due to the weak light absorption ofplanar mono-/multilayers, limited cutoff wavelength edge, and lack of high quality junctions, most reported MoS2-based photodetectors show undesirable performance. Here, a structurized 3D heterojunction of RGO-MoS2/pyramid Si is demonstrated via a simple solution-processing method. Owingto the improved light absorption by the pyramid structure, the narrowedbandgap of the MoS2 by the imperfect crystallinity, and the enhanced chargeseparation/transportation by the inserted reduced graphene oxide (RGO), the assembled photodetector exhibits excellent performance in terms of alarge responsivity of 21.8 A W-1, extremely high detectivity up to 3.8×1015Jones (Jones = cm Hz1/2 W-1) and ultrabroad spectrum response ranging from 350 nm (ultraviolet) to 4.3 μm (midwave infrared). These device parametersrepresent the best results for MoS2-based self-driven photodetectors, andthe detectivity value sets a new record for the 2DMD-based photodetectorsreported thus far. Prospectively, the design of novel 3D heterojunction can beextended to other 2DMDs, opening up the opportunities for a host of high performance optoelectronic devices.
链接：https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201801729
