Research on the Factors Affecting the Growth of Large-Size Monolayer MoS₂ by APCVD.

The transition-metal chalcogenides (TMDs) are gaining increased attention from many scientists recently. Monolayer MoS₂ is an emerging layered TMD material with many excellent physical and electrical properties. It can be widely used in catalysis, transistors, optoelectronics and integrated circuits. Here, the large-sized monolayer MoS₂ is grown on the silicon substrate with a 285-nm-thick oxide layer by atmospheric pressure chemical vapor deposition (APCVD) of sulfurized molybdenum trioxide. This method is simple and it does not require vacuum treatment. In addition, the effects of growth conditions, such as sulfur source, molybdenum source, growth temperature, and argon flow rate on the quality and area of MoS₂ are further studied systematically. These analysis results help to master the morphology and optical properties of monolayer MoS₂. The high quality, excellent performance, and large-size monolayer MoS₂ under the optimal growth condition is characterized by optical microscopy, AFM, XPS, photoluminescence, and Raman spectroscopy. The Raman spectrum and PL mapping show that the grown MoS₂ is a uniform triangular monolayer with a side length of 100 μm, which can pave the way for the applications of photodetectors and transistors.