2024/07/17 by Dengyu Yang, Yang, Dengyu, Qingrui Cao +19
Engineering · #Graphene and Nanomaterials Applications #Advanced Sensor and Energy Harvesting Materials #Modular Robots and Swarm Intelligence
paper · pdf · doi:10.48550/arxiv.2407.12757
The ability to create superlattices in van der Waals (vdW) heterostructures via moiré interference heralded a new era in the science and technology of two-dimensional materials. Through precise control of the twist angle, flat bands and strongly correlated phases have been engineered. The precise twisting of vdW layers is in some sense a bottom-up approach--a single parameter can dial in a wide range of periodic structures. Here, we describe a top-down approach to engineering nanoscale potentials in vdW layers using a buried programmable ferroelectric layer. Ultra-low-voltage electron beam lithography (ULV-EBL) is used to program ferroelectric domains in a ferroelectric Al1-xBxN thin film through a graphene/hexagonal boron nitride (hBN) heterostructure that is transferred on top. We demonstrate ferroelectric field effects by creating a lateral p-n junction, and demonstrate spatial resolution down to 35 nm, limited by the resolution of our scanned probe characterization methods. This innovative, resist-free patterning method is predicted to achieve 10 nm resolution and enable arbitrary programming of vdW layers, opening a pathway to create new phases that are inaccessible by moiré techniques. The ability to "paint" different phases of matter on a single vdW "canvas" provides a wealth of new electronic and photonic functionalities.