Aerosol-assisted chemical vapor deposition of 2H-WS2 from single-source tungsten dithiolene precursors

Abstract

The tungsten carbonyl dimethyldithiolene (dmdt) complexes W(CO)₄(dmdt), W(CO)₂(dmdt)₂, and W(dmdt)₃ were evaluated as potential single-source precursors for the chemical vapor deposition of WS₂. The results of TGA-MS, DIP-MS, and pyrolysis with NMR analysis were consistent with a thermal decomposition pathway in which loss of 2-butyne through a retro[3+2]cycloaddition of the dithiolene ligand generated terminal sulfido ligands. Aerosol-assisted chemical vapor deposition onto silicon substrates was performed using all three complexes, yielding 2H-WS₂ thin films as characterized by Raman spectroscopy and GI-XRD. Film morphology and elemental composition of the films were determined using SEM, EDS, and XPS. Four-point probe measurements afforded a film resistivity of 8.37 Ωcm for a sample deposited from W(dmdt)₃ in toluene at 600 °C.