Nanoscale Control of Homoepitaxial Growth on a Two‐Dimensional Zeolite

Nanoscale crystal growth control is crucial for tailoring two‐dimensional (2D) zeolites (crystallites with thickness less than two unit cells) and thicker zeolite nanosheets for applications in separation membranes and as hierarchical catalysts. However, methods to control zeolite crystal growth with nanometer precision are still in their infancy. Herein, we report solution‐based growth conditions leading to anisotropic epitaxial growth of 2D zeolites with rates as low as few nanometers per day. Contributions from misoriented surface nucleation and rotational intergrowths are eliminated. Growth monitoring at the single‐unit‐cell level reveals novel nanoscale crystal‐growth phenomena associated with the lateral size and surface curvature of 2D zeolites.     

Two‐Dimensional Semiconductors Grown by Chemical Vapor Transport

Developing controlled approaches for synthesizing high‐quality two‐dimensional (2D) semiconductors is essential for their practical applications in novel electronics. The application of chemical vapor transport (CVT), an old single‐crystal growth technique, has been extended from growing 3D crystals to synthesizing 2D atomic layers by tuning the growth kinetics. Both single crystalline individual flakes and continuous films of 1 L MoS₂ were successfully obtained with CVT approach at low growth temperatures of 300–600 °C. The obtained 1 L MoS₂ exhibits high crystallinity and comparable mobility to mechanically exfoliated samples, as confirmed by both atomic resolution microscopic imaging and electrical transport measurements. Besides MoS₂, this method was also used in the growth of 2D WS₂, MoSe₂, Mo_x W_1−x S₂ alloys, and ReS₂, thus opening up a new way for the controlled synthesis of various 2D semiconductors.