Aerosol-Assisted Chemical Vapor Deposition of MoS2 with a Thiourea Sulfur Source: Single-Source Precursors vs Coreactant Mixtures

Aerosol-assisted chemical vapor deposition of MoS2 fromsolutions containing the single-source precursors cis-Mo(CO)(4)(TMTU)(2) and Mo(CO)(5)(TMTU)in toluene was compared to depositions from the coreactant solutioncontaining Mo(CO)(6) and uncoordinated TMTU in toluene. Theresults were used to assess the significance of ligand precoordinationon the properties of the deposited films. Raman spectra and GI-XRDpatterns of the films show that the single-source precursors producedmore intense and sharper signals for 2H-MoS2 as comparedto the coreactant system of Mo(CO)(6) and TMTU, which isindicative of improved crystallinity. SEM and XPS were also used toassess morphology and film composition. Thermolysis of cis-Mo(CO)(4)(TMTU)(2) and analysis of the pyrolysisproducts by GC-MS and H-1 NMR suggested a decompositionmechanism of the TMTU ligand where a terminal sulfido is generatedon the molybdenum center with loss of a heteroatom stabilized carbene.