Controllable growth of wafer-lever MoS2 films by using ex situ heating sulfurization treatment

Abstract

Few-layer MoS₂ films have garnered significant attention as promising materials for electronic devices and sensors due to their exceptional carrier mobility and tunable bandgap. Although various chemical vapor deposition (CVD) techniques have been employed to fabricate few-layer MoS₂ films, there remains a need for film homogeneity, continuity, and crystalline quality improvements. This research used the TVS method to fabricate large-scale few-layered MoS₂ films. The metal Mo films were sulfurized under high vacuum conditions using both in situ and ex situ rapid heating techniques. The in situ treatment method resulted in a mixed phase of MoO₂–MoS₂, whereas the ex situ approach produced uniform and pure polycrystalline 2H-MoS₂ films. By adjusting the thickness of the Mo film, a tri-layer 2H-MoS₂ film grown on a 2-inch sapphire wafer served as the channel material for a top-gate thin-film transistor (TFT). Electrical measurements indicated an n-type semiconductor behavior with a field-effect mobility of 9.2 cm² V s and an I_on/I_off ratio of approximately 10². These results confirm that the ex situ rapid treatment technique effectively grows high-quality, wafer-scale, and layer-controlled few-layer MoS₂ films.