AVS 45th International Symposium
    Surface Science Division Thursday Sessions
       Session SS2-ThA

Paper SS2-ThA3
Growth of Ultrathin ß-MnO@sub 2@ on TiO@sub 2@(110) by Oxygen-Plasma-Assisted Molecular Beam Epitaxy

Thursday, November 5, 1998, 2:40 pm, Room 309

Session: Oxide Growth and Structure
Presenter: S.A. Chambers, Pacific Northwest National Laboratory
Authors: S.A. Chambers, Pacific Northwest National Laboratory
Y. Liang, Pacific Northwest National Laboratory
Correspondent: Click to Email
We have used oxygen-plasma-assisted MBE to grow epitaxial rutile films of pyrolusite (@beta@-MnO@sub 2@) on TiO@sub 2@(110) for thicknesses of 1 to 6 bilayers (BL). We define a BL to be a layer of Mn and lattice O and an adjacent layer of bridging O within the rutile structure. The resulting surfaces have been characterized in-situ by RHEED, LEED, XPS, XPD, and AFM. Well-ordered, pseudomorphic overlayers form for substrate temperatures between 400C and 500C. Mn-Ti intermixing occurs over the time scale of film growth for substrate temperatures in excess of 500C. Films grown at 400-500C exhibit classic Stranski-Krastanov growth whereas those grown at higher temperatures are atomically flat. 1-BL films grown at 450C form a well-ordered surface cation layer of Mn on the rutile structure with at most 10% indiffusion to the second cation layer. Thicker films rapidly disorder due to the simultaneous formation of pyrolusite and ramsdellite (@gamma@-MnO@sub 2@), which is orthorhombic and not lattice matched to TiO@sub 2@(110). However, thin films of rutile pyrolusite are preferentially stabilized by the TiO@sub 2@ substrate. @FootnoteText@ Work supported by the U.S. Department of Energy, Offices of Basic Energy Sciences and Biological and Environmental Research - Environmental Management Science Program.