Effect of Nutral Radical on Sulfur Defect Formation in Monolayer MoS2 Using Microwave Plasma

Molybdenum disulfide (MoS 2 ) is two-dimensional layered materials and have been widely investigated for electronic applications and more. The sulfur defects of MoS 2 are important for its catalytic activity in the hydrogen evolution reaction 1 . Hence it is necessary to form sulfur defects effectively on the basal plane and create more edge sites. In addition, substitution of other elements for the sulfur defects can adjust the Fermi level and the polarity. Low-temperature plasma processing is a powerful technique to introduce sulfur defects and to dope element because of its good control and selectivity. However, high-energy ions cause undesirable sputtering, leading to degradation of the monolayer MoS 2 film. In this study, the effect of neutral radicals on the formation of sulfur defects was investigated by varying particle flux from plasma.