Growth of Large-Area and Highly Crystalline MoS2 Thin Layers on Insulating Substrates

TL;DR

This paper presents a scalable, high-temperature annealing method to synthesize large-area, highly crystalline MoS2 thin layers on insulating substrates, with electrical performance comparable to exfoliated samples, enabling advanced optoelectronic applications.

Contribution

The study introduces a simple, scalable synthesis technique for high-quality, large-area MoS2 layers on insulators, suitable for device fabrication and layered composites.

Findings

Synthesized MoS2 layers are highly crystalline.

Electron mobility in devices is comparable to exfoliated MoS2.

Method is scalable and transferable to various substrates.

Abstract

The two-dimensional layer of molybdenum disulfide (MoS2) 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 MoS2 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 MoS2 thin layers with superior electrical performance on insulating substrates. Spectroscopic and microscopic results reveal that the synthesized MoS2 sheets are highly crystalline. The electron mobility of the bottom-gate transistor devices made of the synthesized MoS2 layer is comparable with those of the micromechanically exfoliated thin sheets from MoS2 crystals. This synthetic approach is simple, scalable and applicable to other transition metal dichalcogenides. Meanwhile, the obtained MoS2 films are transferable to arbitrary substrates, providing great opportunities to make layered composites by stacking various atomically thin layers.