Elucidation of PVD MoS2 film formation process and its structure focusing on sub-monolayer region

Abstract

Abstract Sputtering enables uniform and clean deposition over a large area, which is an issue with exfoliation and chemi-cal vapor deposition methods. On the other hand, the process of physical vapor deposition (PVD) film formationhas not yet been clarified. We prepared several samples from the sub-monolayer region, and performed Ra-man spectroscopy, X-ray photon spectroscopy and high-angle annular dark-field scanning transmission electronmicroscopy. From these results, the internal stresses inherent to PVD films, the bonding states specific to sub-monolayers, and the unique film structure and the grain formation process of PVD films were discussed fromthe perspective of sub-monolayers. As a conclusion, we found that it is important to suppress the formation ofsub-monolayers on the substrate to completely form the first layer.