thin films using chemical vapor deposition: A case study*

The semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDs) have demonstrated promising applications in electronics, optoelectronics, photonics, etc. Molybdenum disulfide (MoS₂) is one of the most explored 2D-TMDs due to its intriguing features and potential for emergent electronics. Apart from that, the valley-related physics in monolayer MoS₂ made it a hot topic of current research. However, the synthesis of defect-free large-scale monolayer MoS₂ with minimal cost is still challenging. Herein, the nucleation and growth of monolayer MoS₂ on two different substrates (SiO₂/Si, mica) via low-pressure chemical vapor deposition is reported. The distance between the precursors (MoO₃/S) and the substrate is also studied for optimal growth. Further, the substrate surface treatment with different agents, like ammonia and other alkali salts, has shown promising results for scaling up monolayer MoS₂ films.