Enhanced Photoresponse in Intermingled WS₂ and MoS₂ Nanodiscs on Graphene Heterostructure Nanohybrids

Abstract Nanohybrids based on van der Waals (vdW) heterostructures of two dimensional (2D) atomic materials have recently emerged as a unique scheme for designing high‐performance quantum sensors. This work explores vdW nanohybrids for photodetection, which consist of graphene decorated with intermingled transition‐metal dichalcogenide (TMDC) nanodiscs (TMDC‐NDs) obtained using wafer‐size, layer‐by‐layer growth. The obtained TMDC‐NDs/graphene nanohybrids take advantage of strong quantum confinement in graphene for high charge mobility and hence high photoconductive gain, and localized surface plasmonic resonance (LSPR) enabled on the TMDC‐NDs for enhanced light absorption. Since the LSPR depends on the nanostructure's size and density, intermingled TMDC‐NDs of different kinds of TMDCs, such as WS₂ (W) and MoS₂ (M), have been found to allow small‐size, high‐concentration TMDC‐NDs to be achieved for high photoresponse. Remarkably, high photoresponsivity up to 31 A/W (550 nm wavelength and 20 µW cm⁻² light intensity) has been obtained on the WMW‐NDs/graphene nanohybrids photodetectors made using three consecutive coatings of WS₂ (1st and 3rd coating) and MoS₂ (2nd coating), which is considerably higher by a factor of ≈4 than that of the counterparts MoS₂‐ND/graphene or WS₂‐NDs/graphene devices. This result provides a facile approach to control the size and concentration of the TMDC‐NDs for high‐performance, low‐cost optoelectronic device applications.