Electrically and Optically-Driven Processes in 2D Heterostructures via In Situ TEM

At the smallest length scales the placement of even a single atom or defect in the periodic arrangement of atoms can alter nanomaterial function, necessitating the development of new techniques for creating and understanding atomically-precise nanostructures. A crucial step in this process involves understanding how individual atoms and atomic-scale defects behave under applied electric or optical fields in nanoscale devices. By using these fields to manipulate atoms and molecules with precision, we can create structures with unique properties that can revolutionize energy storage, conversion, and transmission, as well as quantum computing and sensing.

In this talk, I will focus on how electrical and optical fields during can realize non-equilibrium nanostructures, and their observation using in situ transmission electron microscopy (TEM). We describe the use of a laser-based optical holder to resolve atomic-scale melting and diffusion, developing kinetic models of surface diffusion and phase transformation on 2D materials. Moreover, we utilize in situ straining and electrical biasing to study defect creation, breakdown, and moiré formation in 2D heterostructure stacks. Electric fields can then be utilized to drive the motion of individual surface atoms to form periodic arrays or functional clusters with enhanced optical properties. Knowledge of such atomic responses in electrical and optical fields can in turn be used to tailor atom and defect motion, providing a new window into previously inaccessible atomic-scale nanostructure formation and device dynamics.