The growth of epitaxial iron oxides on platinum (111) as studied by x-ray photoelectron diffraction, scanning tunneling microscopy, and low energy electron diffraction

dc.contributor.author Kim, Yong-ju
dc.date.accessioned 2009-07-15T17:27:04Z
dc.date.available 2009-07-15T17:27:04Z
dc.date.issued 1995
dc.description Thesis (Ph. D.)--University of Hawaii at Manoa, 1995.
dc.description Includes bibliographical references.
dc.description Microfiche.
dc.description xxi, 170 leaves, bound ill. 29 cm
dc.description.abstract For the first time, three complementary surface structure probes, x-ray photoelectron diffraction (XPD), scanning tunneling microscopy (STM), and low-energy electron diffraction (LEED) have been combined in a single instrument. This experimental system has been utilized to study the structure and growth mechanisms of iron oxide films on Pt(111); these films were formed by first depositing a single overlayer of Fe with a certain coverage in monolayers (ML's), and then thermally oxidizing it in an oxygen atmosphere. For films up to ~1 ML in thickness, a bilayer of Fe and O similar to those in FeO(111) is found to form. In agreement with prior studies, STM and LEED show this to be an incommensurate oxide film forming a lateral superlattice with short- and long-range periodicities of ~3.1 C and ~26.0 Å. XPD in addition shows a topmost oxygen layer to be relaxed inward by ~0.6 Å compared to bulk FeO(111) , and these are new structural conclusions. The oxygen stacking in the FeO(111) bilayer is dominated by one of two possible binding sites. For thicker iron oxide films from 1.25 ML to 3.0 ML, the growth mode is essentially Stranski-Krastanov: iron oxide islands form on top of the FeO(111) bilayer mentioned above. For iron oxide films of 3.0 ML thickness, x-ray photoelectron spectroscopy (XPS) yields an Fe 2P3/2 binding energy and an Fe:O stoichiometry consistent with the presence of Fe3O4. Our XPD data further prove this overlayer to be Fe304(111)-magnetite in two almost equally populated domains with a 1800 rotation between them. The structural parameters for this Fe3O4 overlayer generally agree with those of a previous LEED study, except that we find a significant difference in the first Fe-O interplanar spacing. Overall, this work demonstrates the considerable benefits to be derived by using this set of complementary surface structure probes in such epitaxial growth studies.
dc.identifier.uri http://hdl.handle.net/10125/9524
dc.language.iso en-US
dc.relation Theses for the degree of Doctor of Philosophy (University of Hawaii at Manoa). Chemistry; no. 3138
dc.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dc.subject Iron oxides
dc.subject Epitaxy
dc.subject Metal crystals -- Growth
dc.title The growth of epitaxial iron oxides on platinum (111) as studied by x-ray photoelectron diffraction, scanning tunneling microscopy, and low energy electron diffraction
dc.type Thesis
dc.type.dcmi Text
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