Synergistic Effects of Plasmonic Au Nanoislands on a MoSe2 Nanoflake/ZnO Nanorod Heterostructure for an Enhanced Broadband Photoresponse

We report the enhanced photodetection properties of MoSe2/Au-ZnO vertical heterostructures by probing the synergistic effect of Au nanoislands on the optical response of one-dimensional (1D) vertically standing ZnO nanorods (NRs) and few-layer two-dimensional (2D) MoSe2 nanoflakes, collectively. Plasmonic effects mediated strong light-matter interactions in Au-ZnO hybrids are established through spectroscopic studies. A notable red shift accompanied by a quenched intensity of visible photoluminescence of ZnO NRs supports the energy transfer process from ZnO NRs to Au nanoislands in the plasmonic hybrid. The coupling of defect-originated green emission of ZnO NRs with plasmonic absorption (similar to 560 nm) and the strategic position of Au nanoislands facilitate easy transfer of plasmonic charge carriers across the heterojunctions and enhance the signal throughout the total operational bandwidth (up to similar to 900 nm) of the devices considerably. Such robust devices using 2D/1D mixed-dimensional heterostructures and their direct resonant coupling with strategically integrated 0D plasmonic nanoislands make highly responsive (similar to 0.43 A/W) broadband photodetectors for future nanophotonic applications.