CAREER: Atomic Scale Design of van der Waals Heterostructure Nanoribbons

Non-technical Description: Combining two-dimensional (2D) layered materials, such as graphene (one atomic layer of carbon) and transition metal dichalcogenides, to form heterostructures provides innovative routes of tuning electronic and photonic properties of materials on-demand. In addition to vertical stacking of atomic layers, which has been achieved in recent years, novel 2D materials can also be realized by producing quasi-one-dimensional strips, known as nanoribbons. The research component of this CAREER award focuses on understanding of the fundamental science behind synthesizing a new class of materials that are only one-atom thick, with controllable width down to the nanometer scale: van der Waals heterostructure nanoribbons (vdW ribbons). These vdW ribbons may exhibit energy band gaps, ferromagnetism, and half-metallic properties that vary with width and termination of the ribbon edges. The principal investigator is utilizing prior research experience and broad collaborations across academia, industry, and government to develop the foundational theory, synthesis techniques, and device architectures to establish vdW ribbons as a new paradigm in materials science. Importantly, this project prepares graduate and undergraduate students for research and engineering beyond academia by providing opportunities for industrial internships and developing new workshops for bridging the science of these atom-thick materials to the general public.

Technical Description: The predicted properties of two-dimensional heterostructures of transition metal dichalcogenides indicate that these materials have strong potential to impact next-generation optoelectronics. Heterogeneous stacking of the atomic layers while controlling their vertical and lateral dimensions at the nanoscale will significantly enhance the control of the electronic, photonic, and magnetic properties of these novel material systems. More specifically, the objectives of the CAREER award are: 1) Developing theoretical models that predict the optoelectronic and transport properties of vdW heterostructure nanoribbons; 2) Establishing novel metal-organic chemical vapor deposition processes capable of layer-by-layer synthesis with atomic precision; 3) Demonstrating the impact of layer stacking on nanoscale interactions and properties in vdW solids; and 4) Developing fundamental understanding of the roles of edge termination and defect formation on the optoelectronic properties of vdW hetero-ribbons.