Controllable growth of wafer-scale two-dimensional WS₂ with outstanding optoelectronic properties

Abstract As one of two-dimensional (2D) semiconductor materials, transition metal dichalcogenides (TMDs) have sparked enormous potential in next-generation electronics due to their unique and excellent physical, electronic and optical properties. Controllable growth of wafer-scale 2D TMDs is essential to realize the various high-end applications of TMDs, while it remains challenging. Herein, 2 inch 2D WS₂ films were successfully synthesized by ambient pressure chemical vapor deposition based on substrate engineering and space-confined strategies. WS₂ nucleation density can be effectively modulated depending on the annealing conditions of sapphire substrate. The thickness of WS₂ films can be controllably fabricated by adjusting the space-confined height. Moreover, our strategies are demonstrated to be universal for the growth of other 2D TMD semiconductors. WS₂-based photodetectors with different thicknesses were systematically investigated. Monolayer WS₂ photodetector displays large responsivity of 0.355 A W⁻¹ and high specific detectivity of 1.48 × 10¹¹ Jones. Multilayer WS₂ device exhibits negative self-powered photoresponse. Our work provides a new route for the synthesis of wafer-scale 2D TMD materials, paving the way for high performance integrated optoelectronic devices.