Synthesis of 4-in. multilayer molybdenum disulfide via space-confinement thermolysis

Two-dimensional (2D) semiconductors like molybdenum disulfide (MoS2) exhibit superior performance at nanometer-scale thickness compared to silicon. Notably, multilayers are more resistant to breakage during transfer and boast enhanced electrical properties over monolayers. In this study, we synthesized 4-in. multilayer MoS2 using a rapid thermal processing system through the ammonium tetrathiomolybdate precursor thermolysis. A 200 nm-scale space confinement on the sample surface was used to reduce sulfur loss during annealing and to facilitate vacancy healing by self-feeding sulfur atoms. Various characterizations confirmed good crystallinity, surface flatness, and continuity, including Raman spectroscopy, x-ray photoelectron spectroscopy, scanning transmission electron microscopy, and atomic force microscopy. Moreover, these samples showed a significant enhancement in electron mobility. Our approach benefits efficiency, scalability, and procedural simplicity, paving a promising path toward large-scale production of multilayer 2D semiconductors.