Univ. Grenoble Alpes, FR-38000, Grenoble, France, Université de Lyon, C2P2-UMR 5265 (CNRS-Université de Lyon 1-CPE Lyon), Équipe Chimie Organométallique de Surface CPE Lyon, 43 Boulevard du 11 Novembre 1918, Villeurbanne Cedex, France, CEA, INAC SP2 M Minatec Campus, Grenoble Cedex 9, France, Institut Lavoisier de Versailles (ILV), UMR CNRS-UVSQ 8180, 45 avenue des Etats-Unis, Versailles, France, CEA, LETI Minatec Campus, Grenoble Cedex 9, France

The lack of scalable-methods for the growth of 2D MoS2 crystals, an identified emerging material with applications ranging from electronics to energy storage, is a current bottleneck against its large-scale deployment. We report here a two-step ALD route with new organometallic precursors, Mo(NMe2)4 and 1,2-ethanedithiol (HS(CH2)2SH) which consists in the layer-by-layer deposition of an amorphous surface Mo(iv) thiolate at 50 °C, followed by a subsequent annealing at higher temperature leading to ultra-thin MoS2 nanocrystals (?20 nm-large) in the 1-2 monolayer range. In contrast to the usual high-temperature growth of 2D dichalcogenides, where nucleation is the key parameter to control both thickness and uniformity, our novel two-step ALD approach enables chemical control over these two parameters, the growth of 2D MoS2 crystals upon annealing being ensured by spatial confinement and facilitated by the formation of a buffer oxysulfide interlayer. © The Royal Society of Chemistry 2017.

Deposition, Molybdenum compounds, Organometallics, Scalability, Amorphous surfaces, Emerging materials, High-temperature growth, Large-scale deployment, Layer by layer deposition, Organometallic precursors, Spatial confinement, Surface organometallic, Atomic layer deposition