title: Hyperspectral imaging of structure and composition in atomically thin heterostructures.
abstract: Precise vertical stacking and lateral stitching of two-dimensional (2D) materials, such as graphene and hexagonal boron nitride (h-BN), can be used to create ultrathin heterostructures with complex functionalities, but this diversity of behaviors also makes these new materials difficult to characterize. We report a DUV-vis-NIR hyperspectral microscope that provides imaging and spectroscopy at energies of up to 6.2 eV, allowing comprehensive, all-optical mapping of chemical composition in graphene/h-BN lateral heterojunctions and interlayer rotations in twisted bilayer graphene (tBLG). With the addition of transmission electron microscopy, we obtain quantitative structure-property relationships, confirming the formation of interfaces in graphene/h-BN lateral heterojunctions that are abrupt on a micrometer scale, and a one-to-one relationship between twist angle and interlayer optical resonances in tBLG. Furthermore, we perform similar hyperspectral imaging of samples that are supported on a nontransparent silicon/SiO2 substrate, enabling facile fabrication of atomically thin heterostructure devices with known composition and structure.
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Robin W
authors.initials: RW
authors.lastname: Havener
authors.forename: Cheol-Joo
authors.initials: CJ
authors.lastname: Kim
authors.forename: Lola
authors.initials: L
authors.lastname: Brown
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Kevek
authors.forename: Joel D
authors.initials: JD
authors.lastname: Sleppy
authors.forename: Paul L
authors.initials: PL
authors.lastname: McEuen
authors.forename: Jiwoong
authors.initials: J
authors.lastname: Park