A general “gas–liquid” synthesis strategy towards centimeter-scale two-dimensional non-layered semiconductors†

Two-dimensional (2D) non-layered semiconductors have attracted tremendous research interest due to their exotic structural and electronic properties compared with their layered counterparts. However, the lack of large-scale growth methods greatly hinders their application. In this work, we have proposed a gas–liquid heterogeneous reaction strategy to suppress the diffusion of the involved reactants, resulting in the anisotropic growth of centimeter-scale 2D non-layered CdS film at the gas–liquid interface. The thickness of the 2D film can be effectively modulated in the range from 10 to 50 nm by adjusting the viscosity of the liquid solvent. A photodetector designed on the CdS film exhibits a high photoswitching (I_light/I_dark) ratio (up to 2 × 10³), high specific detectivity (∼10¹¹ Jones) and excellent stability. Moreover, centimeter-scale 2D ZnS, TiO₂, SnO₂ and even layered MoS₂ were also obtained by designing corresponding reaction systems, illustrating the apparent universality of the “gas–liquid” strategy. Our results pave a novel avenue for the growth of wafer-scale 2D materials, especially non-layered ones, which will foster their potential applications in integrated optoelectronics.