Broad-Band Photocurrent Enhancement in MoS₂ Layers Directly Grown on Light-Trapping Si Nanocone Arrays

There has been growing research interest in realizing optoelectronic devices based on the two-dimensional atomically thin semiconductor MoS 2 owing to its distinct physical properties that set it apart from conventional semiconductors. However, there is little optical absorption in these extremely thin MoS 2 layers, which presents an obstacle toward applying them for use in high-efficiency light-absorbing devices. We synthesized trilayers of MoS 2 directly on SiO 2 /Si nanocone (NC) arrays using chemical vapor deposition and investigated their photodetection characteristics. The photoresponsivity of the MoS 2 /NC structure was much higher than that of the flat counterpart across the whole visible wavelength range (for example, it was almost an order of magnitude higher at λ = 532 nm). Strongly concentrated light near the surface that originated from a Fabry–Perot interference in the SiO 2 thin layers and a Mie-like resonance caused by the Si NCs boosted the optical absorption in MoS 2 . Our work demonstrates that MoS 2 /NC structures could provide a useful means to realize high-performance optoelectronic devices.