Effects of temperature and pressure on sulfurization of molybdenum nano-sheets for MoS₂ synthesis

The synthesis of high-quality, thickness-controlled molybdenum disulfide (MoS₂) films via vapor-phase growth remains a challenging process. In this work, the synthesis of two-dimensional (2D) MoS₂ films via sputtering and sulfurization in a quartz tube furnace was investigated. Thicknesses of MoS₂ films were dependent on the thickness of Mo films grown using sputtering. The Raman spectra of the MoS₂ films exhibited a 19.12 cm^{− 1} difference between two peaks, including in-plane vibration (E¹_2g) and out-of-plane vibration (A_1g), indicating a monolayer. Room temperature photoluminescence measurements indicate a peak spectral emission at 1.89 eV. Surface morphology of multilayer MoS₂ films and their crystallization processes were observed using atomic force microscopy and scanning electron microscopy. Low temperature (450 °C) synthesis revealed a wide full width at half maximum (FWHM) of both modes, E¹_2g and A_1g, which indicates poor crystallinity. In contrast, using a high sulfurization temperature (750 °C) results in a higher crystallinity or narrow FWHM. Film synthesis at the optimized process conditions (750 °C and a pressure of 1 KPa) produced continuous, uniform, and full-coverage films.