title: Atomically thin mica flakes and their application as ultrathin insulating substrates for graphene.
abstract: By mechanical exfoliation, it is possible to deposit atomically thin mica flakes down to single-monolayer thickness on SiO2/Si wafers. The optical contrast of these mica flakes on top of a SiO2/Si substrate depends on their thickness, the illumination wavelength, and the SiO2 substrate thickness, and can be quantitatively accounted for by a Fresnel-law-based model. The preparation of atomically thin insulating crystalline sheets will enable the fabrication of ultrathin, defect-free insulating substrates, dielectric barriers, or planar electron-tunneling junctions. Additionally, it is shown that few-layer graphene flakes can be deposited on top of a previously transferred mica flake. Our transfer method relies on viscoelastic stamps, as used for soft lithography. A Raman spectroscopy study shows that such an all-dry deposition technique yields cleaner and higher-quality flakes than conventional wet-transfer procedures based on lithographic resists.
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain; Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands. a.castellanosgomez@tudelft.nl.
authors.forename: Andres
authors.initials: A
authors.lastname: Castellanos-Gomez
authors.forename: Magdalena
authors.initials: M
authors.lastname: Wojtaszek
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Tombros
authors.forename: Nicolás
authors.initials: N
authors.lastname: Agraït
authors.forename: Bart J
authors.initials: BJ
authors.lastname: van Wees
authors.forename: Gabino
authors.initials: G
authors.lastname: Rubio-Bollinger