title: Three-dimensional surface topography of graphene by divergent beam electron diffraction.
abstract: There are only a handful of scanning techniques that can provide surface topography at nanometre resolution. At the same time, there are no methods that are capable of non-invasive imaging of the three-dimensional surface topography of a thin free-standing crystalline material. Here we propose a new technique-the divergent beam electron diffraction (DBED) and show that it can directly image the inhomogeneity in the atomic positions in a crystal. Such inhomogeneities are directly transformed into the intensity contrast in the first-order diffraction spots of DBED patterns and the intensity contrast linearly depends on the wavelength of the employed probing electrons. Three-dimensional displacement of atoms as small as 1 angstrom can be detected when imaged with low-energy electrons (50-250 eV). The main advantage of DBED is that it allows visualization of the three-dimensional surface topography and strain distribution at the nanometre scale in non-scanning mode, from a single shot diffraction experiment.
authors.affiliation: Physics Department of the University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
authors.forename: Tatiana
authors.identifier: 0000-0001-6693-8681
authors.initials: T
authors.lastname: Latychevskaia
authors.affiliation: Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan.|Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan.
authors.forename: Wei-Hao
authors.initials: WH
authors.lastname: Hsu
authors.affiliation: Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan.
authors.forename: Wei-Tse
authors.initials: WT
authors.lastname: Chang
authors.affiliation: Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan.
authors.forename: Chun-Yueh
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan.|Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan.
authors.forename: Ing-Shouh
authors.identifier: 0000-0002-7670-1212
authors.initials: IS
authors.lastname: Hwang