Physical investigation of spin-coated MoS₂ films

Amongst emerging Transition Metal Dichalcogenides (TMDCs), molybdenum disulfide (MoS₂) has attracted a remarkable interest thanks to many possible applications. In particular, MoS₂ has potentialities not yet fully realized in solution-based applications. The morphological and the structural properties of MoS₂ films deposited by spin-coating onto Si/SiO₂ substrates were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Micro-Raman Spectroscopy. High resolution AFM imaging highlights the presence of a layered structure. The thickness of each layer is estimated to be around 13 nm. Micro-Raman measurements reveal that there is the coexistence of both 2H-MoS₂ and 1T-MoS₂ phases, which could be useful for electrical applications. Moreover, the band at 290 cm^-1 is assigned to the amorphous phase of MoS₂. The detectability of the mode E_1g in back scattering geometry is ascribed to the disorder of the amorphous phase.