title: In Situ Observations of Free-Standing Graphene-like Mono- and Bilayer ZnO Membranes.
abstract: ZnO in its many forms, such as bulk, thin films, nanorods, nanobelts, and quantum dots, attracts significant attention because of its exciting optical, electronic, and magnetic properties. For very thin ZnO films, predictions were made that the bulk wurtzite ZnO structure would transit to a layered graphene-like structure. Graphene-like ZnO layers were later confirmed when supported over a metal substrate. However, the existence of free-standing graphene-like ZnO has, to the best of our knowledge, not been demonstrated. In this work, we show experimental evidence for the in situ formation of free-standing graphene-like ZnO mono- and bilayer ZnO membranes suspended in graphene pores. Local electron energy loss spectroscopy confirms the membranes comprise only Zn and O. Image simulations and supporting analysis confirm that the membranes are graphene-like ZnO. Graphene-like ZnO layers are predicted to have a wide band gap and different and exciting properties as compared to other ZnO structures.
authors.forename: Huy T
authors.initials: HT
authors.lastname: Quang
authors.affiliation: Institute for Complex Materials, IFW Dresden , P.O. Box D-01171, 01069 Dresden, Germany.|Centre of Polymer and Carbon Materials, Polish Academy of Sciences , M. Curie-Sklodowskiej 34, Zabrze 41-819, Poland.
authors.forename: Alicja
authors.initials: A
authors.lastname: Bachmatiuk
authors.forename: Arezoo
authors.initials: A
authors.lastname: Dianat
authors.forename: Frank
authors.initials: F
authors.lastname: Ortmann
authors.forename: Jiong
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom.
authors.forename: Jamie H
authors.initials: JH
authors.lastname: Warner
authors.affiliation: Erich Schmid Institute of Materials Science, Austrian Academy of Sciences , Jahnstraße 12, A-8700 Leoben, Austria.|Department Materials Physics, Montanuniversität Leoben , Jahnstraße 12, A-8700 Leoben, Austria.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Eckert
authors.forename: Gianaurelio
authors.initials: G
authors.lastname: Cunniberti
authors.affiliation: Institute for Complex Materials, IFW Dresden , P.O. Box D-01171, 01069 Dresden, Germany.|Centre of Polymer and Carbon Materials, Polish Academy of Sciences , M. Curie-Sklodowskiej 34, Zabrze 41-819, Poland.|College of Physics Optoelectronics and Energy, Soochow University , 215006 Suzhou, P. R. China.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Rümmeli
keywords: TEM; ZnO thin films; free-standing membrane; graphene-like ZnO