Visualizing Strain, Stacking and Corrugations in Free-Standing Two-Dimensional Membranes with Advanced Electron Microscopy

Two-dimensional materials are not always uniform and flat, especially after being released from their original substrates. They often exhibit inhomogeneous nanoscale strain, varied stacking orders, and out-of-plane deformations that create corrugations. Despite increasingly advanced synthesis and transfer methods, characterizing these structures in free-standing membranes remains challenging. In this presentation, I will introduce our advancements in state-of-the-art four-dimensional scanning transmission electron microscopy (4D-STEM) and electron ptychography techniques to map strain, stacking order, and out-of-plane morphology in 2D materials. These studies provide significant structural details of suspended 2D membranes, offering insights into their properties and potential applications.