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

Antimony sulfide (Sb 2 S 3 ), 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 Sb 2 S 3 nanosheets on monolayer molybdenum disulfide (MoS 2 ) single crystals is demonstrated, using a low‐temperature chemical vapor deposition process. The density functional theory calculations reveal that MoS 2 lowers diffusion barriers and weakens precursor molecules adsorption, promoting lateral diffusion and 2D growth while suppressing thermodynamically favored 1D morphologies. The resulting 2D Sb 2 S 3 exhibits sub‐8 nm thickness and with lateral dimensions dictated by the underlying MoS 2 single‐crystal template. Remarkably, devices fabricated on the resulted Sb 2 S 3 integrated MoS 2 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 MoS 2 . 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.