Abstract
The two-dimensional layer of molybdenum disulfide (MoS 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 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 2 thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS 2 sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS 2 layer is comparable with those of the micromechanically exfoliated thin sheets from MoS 2 crystals. This synthetic approach is simple, scalable, and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS 2 films are transferable to arbitrary substrates, providing great opportunities to make layered composites by stacking various atomically thin layers. © 2012 American Chemical Society.