Low-Energy Electron Induced Processes in Molecular Thin Films Condensed on Silicon and Titanium Dioxide Surfaces

dc.contributor.advisor Orlando, Thomas M.
dc.contributor.author Lane, Christopher Don en_US
dc.contributor.committeeMember El-Sayed, Mostafa A.
dc.contributor.committeeMember Phillip N. First
dc.contributor.committeeMember Whetten, Robert L.
dc.contributor.committeeMember Zhang, John Z.
dc.contributor.department Chemistry and Biochemistry en_US
dc.date.accessioned 2007-05-25T17:35:20Z
dc.date.available 2007-05-25T17:35:20Z
dc.date.issued 2007-04-09 en_US
dc.description.abstract The focus of the presented research is to examine the fundamental physics and chemistry of low-energy electron-stimulated reactions on adsorbate covered single crystal surfaces. Specifically, condensed SiCl₄ on the Si(111) surface and condensed H₂O on the TiO₂ (110) surface have been studied. By varying adsorbate film thicknesses, the coupling strength of the target molecule to the substrate and surrounding media dictates the progression of the electron induced reactions. To investigate the electron interactions with SiCl₄ on the Si(111) surface, desorbing cations and neutrals were detected via time of flight mass spectrometry (ToF-MS) where neutral chlorine atoms were ionized using a resonance enhanced multi-photon ionization (REMPI) technique. Structure in the cation and neutral yields were assigned to molecular excitations. At an incident electron energy of 10 eV, a resonance structure in the neutral yields was attributed to a negative ion resonance and observed in thick and thin films of SiCl₄. With monoenergetic electrons, specific surface reactions can be controlled which have implications for film growth, surface patterning and masking, and etching. For the H₂O/TiO₂ (110) system, the water interactions with the TiO₂ surface are revealed through the strong electron induced reaction dependencies on the water coverage. Understanding the nonthermal reaction landscape of H₂O on the TiO₂ (110) surface is crucial for developing the system as a catalytic source of hydrogen. The electron-stimulated oxidation of the TiO₂ (110) surface and electron induced sputtering of H ₂O was investigated. Irradiation of water films ([coverage]< 3 ML) oxidized the TiO₂ (110) surface similarly as surface oxidation via O₂ deposition. Each H₂O molecule in the first monolayer seems to be a target for the incoming electron initiating the oxidation. However, water coverages greater than a monolayer limited the oxidation process. The electron-stimulated desorption and sputtering yields of water from the TiO₂ (110) surface were measured as a function of water coverage. Surprisingly, the amount of water sputtered from the surface is nonlinearly dependent on water coverage.
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/14588
dc.publisher Georgia Institute of Technology en_US
dc.subject Silicon tetrachloride en_US
dc.subject Dissociative electron attachment en_US
dc.subject Amorphous solid water en_US
dc.subject Low energy electrons en_US
dc.subject Electron induced oxidation en_US
dc.subject Electron stimulated desorption en_US
dc.subject Sputtering en_US
dc.title Low-Energy Electron Induced Processes in Molecular Thin Films Condensed on Silicon and Titanium Dioxide Surfaces en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Orlando, Thomas M.
local.contributor.corporatename School of Chemistry and Biochemistry
local.contributor.corporatename College of Sciences
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