Enhanced local photoluminescence of a multilayer MoS2 nanodot stacked on monolayer MoS2 flakes

Atomically thin two-dimensional (2D) layered materials, including graphene, boron nitride, and transition metal dichalcogenides (TMDCs), can exhibit novel phenomena distinct from their bulk counterparts. In this work, we report the growth of 2D MoS2 with the configuration of a multilayer MoS2 nanodot stacked on the center of the monolayer MoS2 flake by a single-step and catalyst-free chemical vapor deposition method. The local photoluminescence of the multilayer MoS2 nanodot is significantly enhanced in comparison to that of the basal monolayer MoS2. The reason of this novel phenomenon is owing to the existence of oxygen-related defects, which resulted from the tapered morphology of MoS2 nanodots with many edge states and adsorbed O molecules. The results presented here may open a pathway to modulate the optical properties of future optoelectronic devices using MoS2 flakes with special configuration. (C) 2017 Optical Society of America