Significantly improved photo carrier injection by the MoS2/ZnO/HNP hybrid UV photodetector architecture

A unique ultraviolet (UV) photodetector architecture of MoS2/ZnO/HNP is explored and significantly increased photocurrent (I-ph) of 4 x 10(-3) A is demonstrated under the 385 nm illumination of 54.9 mW/mm(2) at 10 V. This leads to the superior device performance factors: i.e., photoresponsivity of 21,111 mA/W, detectivity of 7.9 x 10(11) jones and EQE of 6,800 %. These device performance factors confirm that the proposed photodetector configuration is superior as compared to the similar versions of ZnO-based UV photodetectors. The hybrid MoS2/ZnO/HNP architecture is constructed by the 2-D transition metal dichalcogenide MoS2 nanoflakes, wide-bandgapZnO quantum dots (QDs) and plasomonic PdAg hybrid nanoparticles (HNPs). The increased I-ph is related to the hot carrier injection through the strongly improved localized surface plasmon resonance (LSPR) by the PdAg HNPs and additional photo carriers from the 2-D MoS2 nanoflakes on top of the original photo-induced carriers in the ZnO QD layer. The PdAg HNPs are fabricated by a unique two-step solid-state dewetting (SSD) technique, having the core-shelled PdAg NPs with the high-density small background Ag NPs. This HNP configuration offers very high-density hot spots and significantly improved LSPR. The photocurrent enhancement of MoS2/ZnO/HNP architecture is systematically studied by the finite-difference time-domain (FDTD) simulations.