Low‐Defect‐Density Monolayer MoS<sub>2</sub> Wafer by Oxygen‐Assisted Growth‐Repair Strategy
Xiaomin Zhang, Jiahan Xu, Aomiao Zhi, Jian Wang, Yue Wang, Wenkai Zhu, Xingjie Han, Xuezeng Tian, Xuedong Bai, Baoquan Sun, Zhongming Wei, Jing Zhang, Kaiyou Wang
Abstract
Abstract Atomic chalcogen vacancy is the most commonly observed defect category in two dimensional (2D) transition‐metal dichalcogenides, which can be detrimental to the intrinsic properties and device performance. Here a low‐defect density, high‐uniform, wafer‐scale single crystal epitaxial technology by in situ oxygen‐incorporated “growth‐repair” strategy is reported. For the first time, the oxygen‐repairing efficiency on MoS 2 monolayers at atomic scale is quantitatively evaluated. The sulfur defect density is greatly reduced from (2.71 ± 0.65) × 10 13 down to (4.28 ± 0.27) × 10 12 cm −2 , which is one order of magnitude lower than reported as‐grown MoS 2 . Such prominent defect deduction is owing to the kinetically more favorable configuration of oxygen substitution and an increase in sulfur vacancy formation energy around oxygen‐incorporated sites by the first‐principle calculations. Furthermore, the sulfur vacancies induced donor defect states is largely eliminated confirmed by quenched defect‐related emission. The devices exhibit improved carrier mobility by more than three times up to 65.2 cm 2 V −1 s −1 and lower Schottky barrier height reduced by half (less than 20 meV), originating from the suppressed Fermi‐level pinning effect from disorder‐induced gap state. The work provides an effective route toward engineering the intrinsic defect density and electronic states through modulating synthesis kinetics of 2D materials.