Wafer-Scale Growth of a MoS2 Monolayer via One Cycle of Atomic Layer Deposition: An Adsorbate Control Method

Monolayer transition metal dichalcogenide compounds with two-dimensional (2D) layered structures may be used as next-generation active materials for electronic and optoelectronic devices. A reliable method for creating high-quality, wafer-scale material with well-controlled large-area growth is required for industrial applications. Two-dimensional material atomic layer deposition (ALD) can be used as an atomically flat monolayer film, but its deposition characteristics limit perfect monolayer formation. Herein, we propose a novel ALD chemical route for uniform monolayer MoS2 film deposition at the wafer scale. We first modulate the precursor injection step to precisely control one cycle's adsorbed precursor amount in a range exceeding a "typical" ALD reaction. Utilizing this process, we successfully created a complete monolayer MoS2 film in one ALD cycle. The film exhibited excellent uniformity at the wafer scale, and its luminescence quantum efficiency was approximately 9 times greater than that of film formed via conventional ALD. These results indicate this method can be employed to obtain complete single layers or to develop high-quality monolayer-scale 2D materials.