Macroscale synthesis of vertical MoS2 -WS2 superlattice heterostructures using Metal-Organic Vapor Deposition

Heterostructures composed of two-dimensional materials facilitate the exploration of novel physics and material properties, which offer great potential for next-generation electronics, optoelectronics, and sensing technologies. While significant progress has been achieved in the fabrication of high-quality, small-scale heterostructures by manual stacking (e.g. mechanical exfoliation), there remains a clear need for scalable, uniform, and reproducible synthesis methods. In addition, reports on the bottom-up synthesis of heterostructures comprising more than two material layers are highly limited. Here, we demonstrate the macroscale synthesis of vertically stacked MoS₂-WS₂ superlattice heterostructures via Metal-Organic Chemical Vapor Deposition. This approach enables controlled and large-scale deposition of superlattice heterostructures composed of seven material layers with tunable thicknesses. The structural and chemical characteristics were thoroughly investigated using a wide range of complementary analytical techniques, e.g. (Scanning) Transmission Electron Microscopy, Grazing Incidence Wide-Angle X-ray Scattering, X-ray Diffraction, Energy-Dispersive X-ray and Raman spectroscopies, (Angle-Resolved) X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry. Notably, uniform bilayer coverage was achieved across large areas for each individual material layer, offering a route applicable to macroscale synthesis of high-quality 2D superlattices.