Enhancement of the Photoresponse of Monolayer MoS2 Photodetectors Induced by a Nanoparticle Grating

Photodetectors based on two-dimensional (2D) materials such as monolayer MoS2 are attractive because they can be directly integrated into the current metal-oxide semiconductor (CMOS) structures. Unfortunately, such devices suffer from low responsivity due to low absorption by the monolayer MoS2. Combining MoS2 with plasmonic nanostructures is an alternative solution for enhancing the absorption of the 2D semiconductor, and this can drastically increase the photoresponsivity of the corresponding photodetector. Herein, a device incorporating a grating-patterned nanoparticle structure is fabricated using traditional photolithography together with an annealing step. We demonstrate that this new structure leads to a strong enhancement in the photocurrent due to the coupling of the MoS2 to localized surface plasmons in the nanoparticle grating. Compared to a simple Au nanoparticle array, the nanoparticle grating structure generates a 100% increase in optical absorption. Thus, under 532 nm illumination, the comp...