- Yu-Chuan Lin, The Pennsylvania State University, State College
Two-dimensional (2D) layered materials such as graphene and transition metal dichalcogenides (TMDs) exhibit unique optoelectronic properties that are not in their bulk counterparts. Integrating 2D layers vertically into van der Waals (vdW) heterostructures can create unprecedented optoelectronic properties. The speaker will present a few examples of synthetic vdW heterostructures (i.e., WSe2-graphene and MoS2-WSe2-graphene) prepared by vapor deposition techniques, such as powder vaporization and metal-organic chemical vapor deposition (MOCVD). The clean, sharp interfaces in synthetic vdW heterostructures, which enable interesting phenomena, such as low-contact resistance between graphene and TMDs and synthetic resonant diodes, will also be discussed. In the second part of the presentation, the speaker will introduce synthetic WSe2 grown on insulating substrates by MOCVD and will provide key insight into the phenomena that control the properties of the epitaxial films. The transistors made of the epitaxial WSe2 exhibit good electrical performance at room temperature, despite the strong material-substrate interactions.