Growth process of molybdenum disulfide thin films grown by thermal vapour sulfurization

Thermal vapour sulfurization is a straightforward method which transforms the spin-coated MoS-based film into MoS₂ thin film. The inhomogeneous surface morphology of deposited MoS₂ thin film changed to homogeneous with lower pinhole density. Also, the emergence of MoS₂(002) X-ray diffraction peak can be seen after the sulfurization process. X-ray photoelectron spectroscopy showed the early formation of MoS₂ bonding at baking stage with the detection of Mo⁴⁺ 3d and S²⁻ 2p core levels. However, the existence of other charges state of Mo 3d before the sulfurization process, indicated that a minimal amount of molybdenum oxide compounds was present. At the sulfurization stage, the difference between Mo 3d_5/2 and S 2p_3/2 photoelectron lines of 67.2 eV was observed which shows the high formation of MoS₂ crystallite. The absorption properties of MoS₂ were detected at ~ 667 nm, ~ 617 nm, and ~ 442 nm. Next, the resonant Raman spectrum estimates the multilayers of MoS₂ were grown. Also, the existence of LA(M) indicates the presence of structural defects and nanoparticle features of MoS₂. High-resolution transmission electron microscopy revealed the growth of vertically aligned MoS₂ planes, namely edge-terminated phenomenon. Polycrystalline quality of MoS₂ was determined by selective area electron diffraction.