Atomic force microscopic studies of oxide thin films on organic self-assembled monolayers
- PDF / 484,692 Bytes
- 12 Pages / 612 x 792 pts (letter) Page_size
- 22 Downloads / 200 Views
MATERIALS RESEARCH
Welcome
Comments
Help
Atomic force microscopic studies of oxide thin films on organic self-assembled monolayers T. P. Niesen,a) M. R. De Guire, J. Bill, and F. Aldinger Max-Planck-Institut f¨ur Metallforschung and Institut f¨ur Nichtmetallische Anorganische Materialien, Universit¨at Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstraße 5, 70569 Stuttgart, Germany
M. R¨uhle Max-Planck-Institut f¨ur Metallforschung, Seestraße 92, 70174 Stuttgart, Germany
A. Fischer, F. C. Jentoft, and R. Schl¨ogl Fritz-Haber-Institut der Max-Planck-Gesellschaft, Abteilung Anorganische Chemie, Faradayweg 4-6, 14195 Berlin, Germany (Received 18 September 1998; accepted 10 February 1999)
The surface morphology of TiO2 - and ZrO2 -based thin films, deposited from aqueous solution at 70–80 ±C onto functionalized organic self-assembled monolayers (SAMs) on silicon has been examined using atomic force microscopy (AFM). The films have been previously shown to consist, respectively, of nanocrystalline TiO2 (anatase) and of nanocrystalline tetragonal ZrO2 with amorphous basic zirconium sulfate. The films exhibit characteristic surface roughnesses on two length scales. Roughness on the nanometer scale appears to be dictated by the size of the crystallites in the film. Roughness on the micron scale is postulated to be related to several factors, including the topography of the SAM and the effects of larger, physisorbed particles or agglomerates. The topographies of the oxide thin films, on both the nanometer and micron scales, are consistent with a particle-attachment mechanism of film growth.
I. INTRODUCTION A. Background
Previous work1–4 has demonstrated that organic selfassembled monolayers (SAMs) on Si can be used as surfaces for the deposition of oxide thin films at low temperatures (,100 ±C) from aqueous solutions. A SAM is an ordered array of long-chain hydrocarbon molecules X-sCH2 dn -Y of a specific length. (In the present work, n 16.) The SAM is anchored to a substrate by covalent bonds that form spontaneously between the surface of the substrate and one of the terminal groups (X) of the hydrocarbon molecule. The other ends of the molecules project away from the substrate, consisting of an ordered two-dimensional array of the surface chemical functionality (Y ). Films containing nanocrystalline TiO2 (anatase),1 tetragonal ZrO2 ,2 SnO2 ,3,5 and FeOOH6 have been deposited on such surfaces. The ceramic films are adherent, microstructurally uniform, and void-free, and have potential for use in electronic, optical, and catalytic applications. The present work describes the surface topography of these films and of the underlying substrates prior to
a)
Address all correspondence to this author. e-mail: [email protected]
2464
http://journals.cambridge.org
J. Mater. Res., Vol. 14, No. 6, Jun 1999
Downloaded: 14 Mar 2015
oxide film deposition, as seen in the atomic force microscope (AFM). Examination of the films in the transmission electron microscope (TEM) is capable of showing the
Data Loading...
