Role of the Spatial Distribution of Gas Flow for Tuning the Vertical/Planar Growth of Nonlayered Two-Dimensional Nanoplates

Despite the difficulty in the orientational growth n control for two-dimensional (2D) materials due to the large anisotropy of surface energy, here we propose a simple growth strategy by adjusting the spatial distribution of the gas flow to tune the vertical/planar growth of nonlayered Cr-based chalcogenide nanoplates. The vertical growth nucleation behaviors are directly related to the distribution of the gas flow and precursor concentration, which are formed by stacking silicon substrates to change the transportation behaviors of the precursor species. The elemental growth steps including nucleation, oriented growth, and the interface formation between the as-grown samples and substrates are characterized by electron microscopy, which concluded that the nucleation of the vertical nanoplates is either achieved from random pregrown polycrystalline nanocrystals or from the amorphous buffer layers. The thickness and density of the nanoplates can be controlled by tuning the height of the airflow barrier and growth conditions. Moreover, an electrostatic-assistance method has been developed to transfer the vertically grown nanoplates to arbitrary surfaces, which could retain very weak interaction with the substrate that largely reduces the electronic influence from the substrates. Our results not only provide a new universal vertical/planar growth method for 2D materials but also hint at a new possibility of pursuing intrinsic 2D magnetic properties and opening the door to explore various 2D magnetic applications and high surface-area-derived applications.

Automated summary

The study proposes a simple growth strategy for nonlayered Cr-based chalcogenide nanoplates by adjusting the spatial distribution of gas flow and characterizes the elemental growth steps through electron microscopy. The results not only provide a new universal growth method but also demonstrate an electrostatic-assistance method to transfer nanoplates to arbitrary surfaces, reducing electronic influence.