Evolution of defect formation during atomically precise desulfurization of monolayer MoS2
Jong‐Young Lee, Jong Hun Kim, Yeonjoon Jung, June Chul Shin, Yangjin Lee, Kwanpyo Kim, Namwon Kim, Arend M. van der Zande, Jangyup Son, Gwan‐Hyoung Lee
Abstract
Abstract Structural symmetry-breaking is a key strategy to modify the physical and chemical properties of two-dimensional transition metal dichalcogenides. However, little is known about defect formation during this process. Here, with atomic-scale microscopy, we investigate the evolution of defect formation in monolayer MoS 2 exposed indirectly to hydrogen plasma. At the beginning of the treatment only top-layer sulfur atoms are removed, while vacancies and the molybdenum atomic layer are maintained. As processing continues, hexagonal-shaped nanocracks are generated along the zigzag edge during relaxation of defect-induced strain. As defect density increases, both photoluminescence and conductivity of MoS 2 gradually decreases. Furthermore, MoS 2 showed increased friction by 50% due to defect-induced contact stiffness. Our study reveals the details of defect formation during the desulfurization of MoS 2 and helps to design the symmetry-breaking transition metal dichalcogenides, which is of relevance for applications including photocatalyst for water splitting, and Janus heterostructures.