A novel 2-step ALD route to ultra-thin MoS₂films on SiO₂through a surface organometallic intermediate

Abstract

The lack of scalable-methods for the growth of 2D MoS 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(NMe) and 1,2-ethanedithiol (HS(CH)SH) 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 MoS 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 MoS crystals upon annealing being ensured by spatial confinement and facilitated by the formation of a buffer oxysulfide interlayer.

A Tunable Bimetallic MOF‐74 for Adsorption Chiller Applications

“…These isotherms for the pure MOF‐74 samples namely Ni 100 Zn 0 and Ni 0 Zn 100 were consistent with previous results of CO 2 adsorption. [4b], As evident from the shape of desorption curves, CO 2 adsorption is reversible for all bimetallic MOF‐74 samples with negligible hysteresis.…”

“Green” Synthesis of Metal‐Organic Frameworks

“…Just recently several studies dealt with the synthesis of these compounds under rather green condition. It was reported that already the ligand molecule can be obtained without using organic solvents by adding hydroquinone to molten potassium formate under a stream of CO 2 . The thus obtained linker molecule can be further converted into Ni‐CPO‐27 under reflux conditions with nickel acetate in water for one hour.…”

Controlled Electrochemical Deposition of Large‐Area MoS2 on Graphene for High‐Responsivity Photodetectors

“…During recent years, heterostructures of atomically thin 2D materials have emerged in a large amount and opened up unprecedented opportunities to artificially design and tune the 2D heterojunctions with predefined optical and electrical properties . In recent years, a number of approaches in the synthesis of single 2D material in wafer scale have been reported, including CVD ( chemical vapour deposition ) graphene on copper using gaseous methane or solid carbon sources, MOCVD (metal‐organic CVD) monolayer molybdenum disulphide (MoS 2 ) on insulating SiO 2 from gas‐phase precursors of Mo(CO) 6 , and the growth of MoS 2 films by the sulfurization of MoO 3, a direct elemental chemical reaction of Mo film and sulfur, and a novel 2‐step atomic layer deposition process using the special molecular precursors Mo(NMe 2 ) 4 and 1,2‐ethanedithiol (HS(CH 2 ) 2 SH), as well as the thermolysis of ammonium thiomolybdate (NH 4 ) 2 MoS 4 . Moreover, as active catalysts for hydrogen evolution, MoS 2 nanoclusters/films have been obtained by electrochemical deposition on traditional 3D substrates such as conducting glasses or metals from (NH 4 ) 2 MoS 4 .…”