Wafer-scale formation of MoS2 with controlled thickness and high uniformity via conversion of MoOx using H2S sulfurization and subsequent crystallization

Achieving uniform, high-quality, and thickness-controlled two-dimensional semiconductor films at the wafer scale remains a critical challenge for practical device integration. This work presents a scalable synthesis method for MoS₂ films on Si/SiO₂ wafers using a three-step conversion (3SC) process. The process comprises the deposition of an amorphous MoO_x film, low-temperature high-pressure H₂S annealing for sulfurization, and high-temperature Ar annealing to enhance crystallinity. Precise thickness control, from monolayer to ~ 20 nm, is realized by adjusting the initial MoO_x thickness. A higher oxygen content in MoO_x improves sulfurization efficiency and promotes uniform conversion to MoS₂. Structural and optical characterizations using Raman and Photoluminescence (PL) spectroscopy confirm enhanced crystallinity, with a PL-FWHM narrowed to ~ 0.08 eV. The 3SC method achieves uniform MoS₂ coverage across the entire wafer, demonstrating its compatibility with large-area fabrication and its potential for future electronics and optoelectronics applications.