title: Direct imaging of a two-dimensional silica glass on graphene.
abstract: Large-area graphene substrates provide a promising lab bench for synthesizing, manipulating, and characterizing low-dimensional materials, opening the door to high-resolution analyses of novel structures, such as two-dimensional (2D) glasses, that cannot be exfoliated and may not occur naturally. Here, we report the accidental discovery of a 2D silica glass supported on graphene. The 2D nature of this material enables the first atomic resolution transmission electron microscopy of a glass, producing images that strikingly resemble Zachariasen's original 1932 cartoon models of 2D continuous random network glasses. Atomic-resolution electron spectroscopy identifies the glass as SiO(2) formed from a bilayer of (SiO(4))(2-) tetrahedra and without detectable covalent bonding to the graphene. From these images, we directly obtain ring statistics and pair distribution functions that span short-, medium-, and long-range order. Ab initio calculations indicate that van der Waals interactions with graphene energetically stabilizes the 2D structure with respect to bulk SiO(2). These results demonstrate a new class of 2D glasses that can be applied in layered graphene devices and studied at the atomic scale.
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Pinshane Y
authors.initials: PY
authors.lastname: Huang
authors.forename: Simon
authors.initials: S
authors.lastname: Kurasch
authors.forename: Anchal
authors.initials: A
authors.lastname: Srivastava
authors.forename: Viera
authors.initials: V
authors.lastname: Skakalova
authors.forename: Jani
authors.initials: J
authors.lastname: Kotakoski
authors.forename: Arkady V
authors.initials: AV
authors.lastname: Krasheninnikov
authors.forename: Robert
authors.initials: R
authors.lastname: Hovden
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Mao
authors.forename: Jannik C
authors.initials: JC
authors.lastname: Meyer
authors.forename: Jurgen
authors.initials: J
authors.lastname: Smet
authors.forename: David A
authors.initials: DA
authors.lastname: Muller
authors.forename: Ute
authors.initials: U
authors.lastname: Kaiser
mesh_terms: D005898:Glass / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D012822:Silicon Dioxide; D006108:Graphite