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

Aerosol-assisted chemical vapor deposition of MoS 2 from solutions 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 solution containing Mo(CO) 6 and uncoordinated TMTU in toluene. The results were used to assess the significance of ligand precoordination on the properties of the deposited films. Raman spectra and GI-XRD patterns of the films show that the single-source precursors produced more intense and sharper signals for 2H-MoS 2 as compared to the coreactant system of Mo(CO) 6 and TMTU, which is indicative of improved crystallinity. SEM and XPS were also used to assess morphology and film composition. Thermolysis of cis -Mo(CO) 4 (TMTU) 2 and analysis of the pyrolysis products by GC–MS and 1 H NMR suggested a decomposition mechanism of the TMTU ligand where a terminal sulfido is generated on the molybdenum center with loss of a heteroatom stabilized carbene.