Ji Qingqing, Su Cong, Mao Nannan, Tian Xuezeng, Idrobo Juan-Carlos, Miao Jianwei, Tisdale William A, Zettl Alex, Li Ju, Kong Jing
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Sci Adv. 2021 Oct 29;7(44):eabj3274. doi: 10.1126/sciadv.abj3274. Epub 2021 Oct 27.
Achieving large-size two-dimensional (2D) crystals is key to fully exploiting their remarkable functionalities and application potentials. Chemical vapor deposition growth of 2D semiconductors such as monolayer MoS has been reported to be activated by halide salts, for which various investigations have been conducted to understand the underlying mechanism from different aspects. Here, we provide experimental evidence showing that the MoS growth dynamics are halogen dependent through the Brønsted-Evans-Polanyi relation, based on which we build a growth model by considering MoS edge passivation by halogens, and theoretically reproduce the trend of our experimental observations. These mechanistic understandings enable us to further optimize the fast growth of MoS and reach record-large domain sizes that should facilitate practical applications.
获得大尺寸二维(2D)晶体是充分发挥其卓越功能和应用潜力的关键。据报道,卤化物盐可激活二维半导体(如单层MoS)的化学气相沉积生长,针对此已开展了各种研究,从不同方面了解其潜在机制。在此,我们提供实验证据表明,基于布朗斯特-埃文斯-波拉尼关系,MoS的生长动力学取决于卤素,据此我们通过考虑卤素对MoS边缘的钝化作用建立了一个生长模型,并从理论上再现了我们实验观察的趋势。这些机理认识使我们能够进一步优化MoS的快速生长,并达到创纪录的大尺寸区域,这将有助于实际应用。