Dopant-Induced Giant Photoluminescence of Monolayer MoS2 by Chemical Vapor Transport

Substitutional doping of 2D transition metal dichalcogenides (TMDCs) has been recognized as a promising strategy to tune their optoelectronic properties for a wide array of applications. However, controllable doping of TMDCs remains a challenging issue due to the natural doping of these materials. Here, the controllable growth of Ti-doped MoS2 monolayers is demonstrated via the chemical vapor transport method, and the atomic embedded structure is confirmed by scanning transmission electron microscope with a probe corrector measurements. Furthermore, the grown Ti-doped MoS2 monolayer exhibits giant photoluminescence (PL), 85-fold stronger than a pristine MoS2 monolayer prepared by the same method. The giant PL enhancement is attributed to dopant-induced O-Ti-S units and improved interaction between the monolayer and the mica substrate, increasing the photoluminescence quantum yield and facilitating radiation recombination. The successful growth of Ti-doped MoS2 monolayer and the improvement of its optical and electrical properties by Ti doping may provide a promising method to engineer the optoelectronic properties of 2D TMDCs materials.