Wafer-scale MOCVD growth of monolayer MoS2 on sapphire and SiO2

High-quality and large-scale growth of monolayer molybdenum disulfide (MoS 2 ) has caught intensive attention because of its potential in many applications due to unique electronic properties. Here, we report the wafer-scale growth of high-quality monolayer MoS 2 on singlecrystalline sapphire and also on SiO2 substrates by a facile metal-organic chemical vapor deposition (MOCVD) method. Prior to growth, an aqueous solution of sodium molybdate (Na2MoO4) is spun onto the substrates as the molybdenum precursor and diethyl sulfide ((C 2 H 5 ) 2 S) is used as the sulfur precursor during the growth. The grown MoS 2 films exhibit crystallinity, good electrical performance (electron mobility of 22 cm 2 ·V -1 ·s -1 ) and structural continuity maintained over the entire wafer. The sapphire substrates are reusable for subsequent growth. The same method is applied for the synthesis of tungsten disulfide (WS 2 ). Our work provides a facile, reproducible and cost-efficient method for the scalable fabrication of high-quality monolayer MoS 2 for versatile applications, such as electronic and optoelectronic devices as well as the membranes for desalination and power generation.