Diffusion-Mediated Synthesis of MoS₂/WS₂ Lateral Heterostructures

Abstract

Controlled\ngrowth of two-dimensional transition metal dichalcogenide (TMD) lateral\nheterostructures would enable on-demand tuning of electronic and optoelectronic\nproperties in this new class of materials. Prior to this work, compositional\nmodulations in lateral TMD heterostructures have been considered to\ndepend solely on the growth chronology. We show that in-plane diffusion\ncan play a significant role in the chemical vapor deposition of MoS₂/WS₂ lateral heterostructures leading to a variety\nof nontrivial structures whose composition does not necessarily follow\nthe growth order. Optical, structural, and compositional studies of\nTMD crystals captured at different growth temperatures and in different\ndiffusion stages suggest that compositional mixing versus segregation\nare favored at high and low growth temperatures, respectively. The\nobserved diffusion mechanism will expand the realm of possible lateral\nheterostructures, particularly ones that cannot be synthesized using\ntraditional methods.