Growth of Large-Area and Highly Crystalline MoS sub(2) Thin Layers on Insulating Substrates

The two-dimensional layer of molybdenum disulfide (MoS sub(2)) has recently attracted much interest due to its direct-gap property and potential applications in optoelectronics and energy harvesting. However, the synthetic approach to obtain high-quality and large-area MoS sub(2) atomic thin layers is still rare. Here we report that the high-temperature annealing of a thermally decomposed ammonium thiomolybdate layer in the presence of sulfur can produce large-area MoS sub(2) thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS sub(2) sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS sub(2) layer is comparable with those of the micromechanically exfoliated thin sheets from MoS sub(2) crystals. This synthetic approach is simple, scalable, and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS sub(2) films are transferable to arbitrary substrates, providing great opportunities to make layered composites by stacking various atomically thin layers.