Hosted by: Mircea Cotlet

Van der Waals (vdW) layered materials open up new opportunities in modern electronics as they can be readily isolated into atomically thin monolayers, resulting in two-dimensional (2D) confinement of carriers. vdW heterostructures formed by stacking these 2D materials as building blocks have a wide range of optoelectronic properties and unprecedent physical phenomena. By using cathodoluminescence in electron microscope, I will show here how the structural properties of interfaces of vdW heterostructures play roles in the optical emission and charge carrier transport. In particular, I will discuss the effect of (1) twisted interface, (2) heterointerface, and (3) deformed (curved) interface on the luminescence. I demonstrate (1) tunable optical emission controlled by twist angle, (2) nanoscale optical/structure characterization of a monolayer transition metal dichalcogenides, and (3) enhanced luminescence by optical cavity effect of vdW heterostructures.