Physical Investigation of Spin-Coated MoS2 Films

Abstract: Among emerging Transition Metal Dichalcogenides (TMDCs), molybdenum disulfide (MoS2) has attracted a remarkable interest due to its 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 a coexistence between 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 E1g in back scattering geometry is ascribed to the disorder of the amorphous phase.