MoS<sub>2</sub> Nanoflake and ZnO Quantum Dot Blended Active Layers on AuPd Nanoparticles for UV Photodetectors
Shusen Lin, Rutuja Mandavkar, Rakesh Kulkarni, Shalmali Burse, Md Ahasan Habib, So Hee Kim, Mingyu Li, Sundar Kunwar, Jihoon Lee
Abstract
A hybrid UV photodetector incorporating a blended active layer of molybdenum disulfate (MoS2) nanoflakes and zinc oxide (ZnO) quantum dots (QDs) on the Au core–shelled AuPd hybrid NPs (HNPs), namely, the MoS2*ZnO/HNP configuration, is demonstrated for the first time. In the proposed configuration, the hot carriers generated by the strong localized surface plasmon resonance (LSPR) of Au-shelled AuPd HNPs can be effectively collected at the ZnO QD’s conduction band. The blended MoS2 nanoflakes also successfully absorb the high-energy photons, offering additional photocarriers. The optimized device demonstrates an increased photocurrent (Iph) of 1.49 × 10–3 A at 10 V under 54.9 mW/mm2, which offers improved performance parameters of a photoresponsivity (R) of 2,525 mA/W, a detectivity (D) of 7.251 × 1011 jones, and an external quantum efficiency (EQE) of 813% at 0.34 mW/mm2. The result is one of the best ZnO-based photodetectors demonstrated so far. The enhanced photocurrent is due to the greater photocarrier injections by the blended active layer of MoS2 nanoflakes and ZnO QDs on the Au-shelled AuPd HNPs. The finite-difference time-domain (FDTD) simulation confirms the significantly increased maximum local e-field intensity and hotspots of the MoS2*ZnO/HNP blended active layer.