Pressure-dependent sulfurization of molybdenum thin films for high-quality MoS₂ formation

Abstract The synthesis of molybdenum disulfide (MoS 2 ) through the sulfurization of molybdenum (Mo) thin films has garnered significant attention for applications in electronics and energy devices. This study investigates the effect of varying the pressure within the sulfurization chamber on the quality and properties of MoS 2 films. Mo thin films deposited on soda lime glass substrates were subjected to sulfurization under controlled temperatures in a quartz tube furnace, with chamber pressures ranging from 50 to 300 Torr. The impact of these pressure variations on the crystallinity and morphology of the films was assessed using Raman spectroscopy, Hall measurements, and Field Emission Scanning Electron Microscopy (FESEM). At lower pressures (50 and 150 Torr), the sulfurization process yielded MoS 2 films with higher defects due to sulfur vacancies, evidenced by the presence of a more pronounced satellite Raman peak at ∼380 cm −1 . Conversely, higher pressures (200 and 300 Torr) produced films with enhanced crystallinity, as indicated by the narrower Raman characteristic peak of MoS 2 at ∼405 cm −1 and more uniform morphology observed in FESEM images. Furthermore, films sulfurized at higher pressures exhibited a shift from n-type to p-type conductivity, suggesting the effective passivation of sulfur vacancies under these conditions. The optimized sulfurization condition at 300 Torr resulted in continuous, nearly defect-free MoS 2 films with superior electrical characteristics, including increased carrier mobility. These findings underscore the critical role of sulfurization chamber pressure in modulating the structural and electronic properties of MoS 2 films, offering valuable insights for optimizing large-scale production processes for electronic and photovoltaic applications.