Pt-Nanostrip-Enabled Plasmonically Enhanced Broad Spectral Photodetection in Bilayer MoS2

Hot electron injection in 2D layered materials, in particular graphene or transition metal dichalcogenides, has been the subject of intense research in recent years. The coupling of plasmonic nanostructures with the nanolayers of 2D materials enhances the optoelectronic properties even beyond the bandgap of the material and depends on the tuning of the plasmonic nanomaterials used. In contrast to the Au/Ag mostly used in plasmonic nanostructures, Pt/Pd are more promising for the design of future nano-plasmonic devices due to their strong catalytic activities and they exhibit a broad localized surface plasmon resonance. Here, plasmonic enhancements in the photoconductivity of bilayer MoS2 induced by Pt nanostrips are reported. About three orders of change in the photocurrent was observed when the plasmonic Pt nanostrips were integrated with the MoS2 and this was measured under illumination with a 532-nm laser. The fabricated MoS2 devices with Pt nanostrips demonstrated a sensitivity to UV, visible, and NIR light. Numerical analysis shows that the platinum nanostrips exhibit better absorption properties over a broader range of the light spectrum. The electric field enhancements observed at 532 nm and 980 nm clearly indicate that MoS2-based nanodevices can be tuned with Pt plasmonic nanostructures to achieve high-performance, ultra-compact, optoelectronic devices with excellent plasmonic and catalytic activities.