A hybrid device scheme is an attractive strategy in the construction of advanced UV photodetectors due to the flexibility in selecting the components and correspondingly improved optoelectronic properties by the cooperation of various components, which cannot be achieved by a single component device. In this work, a novel hybrid UV photodetector (PD) is demonstrated by adapting AuPt alloy hybrid nanoparticles (AHNPs), ZnO quantum dots (QDs), and graphene quantum dots (GQDs), namely, GQD/ZnO/AHNP PD. The optimized device achieves high-end figure-of-merit performance with a responsivity of 2299 mA/W, detectivity of 7.04 × 1010 jones, and external quantum efficiency of 741%. Enhanced photocurrent can be associated with the hot electron generation around the AuPt AHNPs and swift transfer to the conduction band of ZnO QDs. At the same time, the added carrier injection is achieved by a thin layer of GQDs. High density of hotspots and electromagnetic fields are generated by the strong localized surface plasmon resonance (LSPR) by the uniquely designed AuPt AHNPs with the fully alloyed AuPt NPs and adjacent small background Au NPs. The e-field distribution of various NP configurations is systematically investigated with finite-difference time-domain (FDTD) simulations.
Keywords: AuPt alloy hybrid nanoparticles (AHNPs); GQD; LSPR; SSD; UV photodetector; ZnO.