Van der Waals Template-Assisted Growth of Two-dimensional Sb₂S₃

Antimony sulfide (Sb₂S₃), a representative of the pnictogen chalcogenide family, possesses a tunable bandgap, strong optical absorption, and phase-change functionality, making it a promising candidate for next-generation optoelectronic and memory devices. However, its intrinsic quasi-one-dimensional (1D) crystal structure favors nanowire or nanorod growth, hindering synthesis in two-dimensional (2D) form and limiting integration into ultrathin planar device architectures. Here, van der Waals (vdW) template-assisted growth of atomically thin 2D Sb₂S₃ nanosheets on monolayer molybdenum disulfide (MoS₂) single crystals is demonstrated, using a low-temperature chemical vapor deposition process. The density functional theory calculations reveal that MoS₂ lowers diffusion barriers and weakens precursor molecules adsorption, promoting lateral diffusion and 2D growth while suppressing thermodynamically favored 1D morphologies. The resulting 2D Sb₂S₃ exhibits sub-8 nm thickness and with lateral dimensions dictated by the underlying MoS₂ single-crystal template. Remarkably, devices fabricated on the resulted Sb₂S₃ integrated MoS₂ heterostructure demonstrate broadband photodetection from ultraviolet to near-infrared, with photoresponsivity enhanced by two orders of magnitude and improved field-effect mobility compared to bare monolayer MoS₂. These results establish a scalable route to access 2D forms of quasi-1D chalcogenides, bridging the critical gap between theoretical predictions and practical applications while enabling their integration into ultrathin, interface-engineered optoelectronic and memory devices.