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.