CVD synthesis and optical study of bandgap-tunable Sn-doped monolayer molybdenum disulfide

Two-dimensional transition metal dichalcogenides (TMDCs) have attracted extensive interest in next-generation optoelectronic devices and energy-harvesting absorbers due to their fascinating optical and electronic properties. It is of great interest to engineer the electronic structure of TMDCs to attain more intriguing physical properties. Here, we introduce SnCl₂ as a low-cost, environmentally friendly dopant to simultaneously engineer the band structure of monolayer MoS₂ and this is an easily scalable and high-quality, efficient one-step CVD method, revealing that the tensile strain induced by the different bond lengths of Sn-S and Mo-S can directionally modulate the electronic state of monolayer MoS₂ and lead to bandgap reforming, providing a feasible way for bandgap engineering. Our work demonstrates the effective modulation of TMDC's bandgap to expand the novel optoelectronic properties of 2D materials.