Layered Electrostatic Heterostructures for Electronics and Photonics

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

Non-technical Description: When a material's size is reduced to atomic dimensions, material properties become profoundly altered, and new opportunities emerge for discovering useful phenomena. An important example of this occurs in two dimensional materials, which are sheet-like objects that are just a few atoms thick. This project addresses fundamental challenges in understanding the behavior of these materials when the two dimensional materials are stacked on top of each other to build a multi-layered composite. The materials synthesized in this project are useful for information technology and energy conversion and storage. The research in this project is integrated into many aspects of outreach and education. The students who work on this project are exposed to advanced challenges in materials synthesis and characterization. This project also engages the broader public through several activities, including outreach to high-school students through demonstrations that use art supplies such as graphite, clay, and mica - all of which are built from two dimensional materials - to engage students in scientific inquiry. Technical Description: Recent observations of emergent properties in few-flake stacks of graphene, boron nitride, and dichalcogenides, termed van der Waals heterostructures, have generated immense interest because of their remarkable electronic, optical, chemical, and mechanical properties. All of the studied van der Waals heterostructures are held together primarily by weak van der Waals interactions, highlighting an opportunity to design and understand multilayered materials that are held together by stronger forces, especially electrostatic forces. The primary research goal is to build model heterostructures and understand the principles that relate their structure to their electronic and photonic properties. This project combines experimental and theoretical approaches, including microspectroscopy to assess the optical properties, conductivity measurements to assess electronic coupling and charge transfer, and photoemission spectroscopy coupled with density functional theory calculations to assess band structure. Ultimately, an understanding of the structure-property relationships in these heterostructures can provide an important framework for designing the optoelectronic properties of these new materials.